I have already thought of TFT screens behind dummy front panels but it's a lot of work, particularly fiddly mechanical which is the bit I hate doing most. Also it would likely need doing in a different way for each bit of kit (reinventing the wheel) unless I was fortunate enough to acquire a job lot of identical scopes for a bargain price which is hard to do.
Here you have lots of sexy looking potential dummy front panels 
(Search for lecroy for parts, for instance)
http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR0.TRC0.H0.Xlecroy+for+parts.TRS0&_nkw=lecroy+for+parts&_sacat=0
Thanks but most of what comes up for me are old monochrome tubed equipment. The ones with flat screens are still unaffordable.
If you are into electronics, you could defeat a soft power on button with a relay and/or transistor with a NE555 timer circuit or something, connected to the soft power switch. So that your electronics fix, makes it get a power on press, 5 or 10 seconds, after power is applied. But booting into the right initial screen(s), is not so easy either.
Maybe it's better to build prop oscilloscopes. Buy some broken/for parts oscilloscopes from eBay, and replace the screen. Install a screen connected to a Raspberry Pi or something, and just have them play a video of an oscilloscope screen or something like that.
It would make it reproducible
That is a good idea. It could then go through various electronics waveform screen shots.
An alternative, would be to connect a few of the buttons to an MCU, and program a button sequence (such as (hypothetically), wait 7 seconds after initial power up, then "press" soft power on button, wait 5 seconds, then "press" Recall, user settings #1. Then the scope will display something nice, in my hypothetical example).
But I don't think the OP has the resources to pay for this to be done by someone, and they may not know how to do this themselves and/or not want to spend the time to do it.
I would indeed like to be able to do that but it's down to there not being enough hours in the day. Also I do tend to cling onto the idea of real working oscilloscopes. Most of the time they're used for displaying wiggly lines in the background but sometimes an actor will be using it for its proper purpose of stabbing a probe around a circuit board with alternating expressions of puzzlement & delight. When I tell the production buyers this is how they should be used, they're always amazed!
Regardless of which scope is shown with the label obscured, the experts in the field will be able to tell you the brand and probably date of manufacture.
Given that, I wonder if truly low end stuff is the way to go. A Rigol DS1054Z? In a lab? Seriously? Keysight, older Agilent, even older Tektronix analog scopes, sure. 1054Z? Never going to happen.
THIS exactly! 
A low end scope simply doesn't look the part, and I doubt a cheapish looking (even for the average consumer) scope with tiny screen is cutting it unless the scene shows engineers being broke. And as rstofer says, to anyone who ever saw the inside of a real lab seeing a Hantek or Rigol in a scene depicting a professional lab is probably cringe-worthy at best.
If the budget is tight and sponsoring isn't an option for some reason then I'd scour the 2nd hand market for some old big brand digital scopes. A few hundred bucks can buy you a lot there, and unlike the Hantek/Rigol solution doesn't immediately scream "cheap" 
The last option would be to just rent a proper looking scope from a lab or a rental provider.
A low end modern scope is still going to look better than an old scope. The presence of different coloured traces & detailed text on the screen makes a big difference. Another good reason for preferring modern TFT ones to old but quality tubed ones is that they're much shallower & lighter. Set builders rarely understand how deep an EE's bench needs to be so frequently items are rejected once on set as they overhang the bench front. And then there's the weight issue. Often old scopes are destroyed by their own weight when the front panel is crashed while being carried carelessly through a door way for instance. I have a nice Tek 7000 series which has been completely ruined by all the attenuator & timebase knobs being bent through 90 degrees in such a way.
On ebay here in the UK there are very few used digital scopes ever showing. One old 25MHz sold recently for over £100 & in all likelihood the cold cathode backlight for the TFT will be unusably dim.
I think it's very rare for production companies to hire real gear from the likes of Livingstone Hire etc. The buyer for the most recently released Bond movie told me that the director had decided to have all the electronics laboratory instruments made from scratch by a team of prop makers. I whinced when I heard this & haven't seen this film yet as I feel it'd be just too painful to watch! Can anyone who's seen it comment? They could have hired some really tasty modern gear from Livingstone, had one of their techs on set to install & supervise it & it would be cheaper.
I would indeed like to be able to do that but it's down to there not being enough hours in the day. Also I do tend to cling onto the idea of real working oscilloscopes. Most of the time they're used for displaying wiggly lines in the background but sometimes an actor will be using it for its proper purpose of stabbing a probe around a circuit board with alternating expressions of puzzlement & delight. When I tell the production buyers this is how they should be used, they're always amazed!
The Siglent SDS1052DL, about £195, seems to have a real solid on/off switch, but I'm NOT 100% sure (ideally you need to check, e.g. by asking the seller, by email). But it does look like one, on the very top, left hand side.
If that is the case, your only instructions to the film crew, may only be press the "AutoSet/AUTO" button, if someone messes it up.
Then plug some kind of demo signal board into it, such as a cheap ebay signal generator, or something, those small PCB afairs, for about £20 or so. To give it some pretty real life pictures.
They can then probe about for real if wanted, as it will still work.
http://www.ebay.co.uk/itm/Siglent-SDS1052DL-Digital-Storage-Oscilloscope-7-LCD-50MHZ-500MSa-s-32Kpts-UK-/222241837316?hash=item33bea55104:g:-wAAAOSwZVlXwTz1
I think, the idea with the Logic Analyzer running Windows is the best so far.
There's just a few buttons on the front and no BNC-Connectors that can be bent, just the ribbon-connectors for the cables.
Make a few videos of the device that shows different signals and also tell production companies that they can put their custom stuff on it to show whatever they want.
That's probably the best solution money can buy.
The Alternative would be to build some custom front-panel out of metal and put a TFT-Screen in there to play video. I'm guessing that that would cost less than 500€ and is durable enough to survive the rough handling on set.
I know this may get very negative feelings from most of you (it is abuse after all),
But if you do the thing with a 555 timer or Arduino, etc, to control the button contacts,
then after setting the thing, and saving as a default or auto, pull off all the knobs, squirt some glue in there, and put all the knobs back on.
No more finger Trouble (Hopefully the software doesn't glitch out and forget its settings)
I think, the idea with the Logic Analyzer running Windows is the best so far.
Or any Windows based scope or gut it and put a readily made video player inside (put a USB stick in the rear and it will play the video from it). Actually you could go as far by replacing all the knobs with solid steel ones and powder coat them for durability. IOW: turn a scope in a prop.
A low end modern scope is still going to look better than an old scope. The presence of different coloured traces & detailed text on the screen makes a big difference. Another good reason for preferring modern TFT ones to old but quality tubed ones is that they're much shallower & lighter. Set builders rarely understand how deep an EE's bench needs to be so frequently items are rejected once on set as they overhang the bench front. And then there's the weight issue. Often old scopes are destroyed by their own weight when the front panel is crashed while being carried carelessly through a door way for instance. I have a nice Tek 7000 series which has been completely ruined by all the attenuator & timebase knobs being bent through 90 degrees in such a way.
On ebay here in the UK there are very few used digital scopes ever showing. One old 25MHz sold recently for over £100 & in all likelihood the cold cathode backlight for the TFT will be unusably dim.
You've got so many requirements you aren't going to find anything to match it, there have been some great suggestions in here but consider that you might have to build something. A late 80's to early 2000's front panel from a scope or spectrum analyser could be found for a few hundred which gets you the look and knobs (screw them through metal plate from behind the panel so they can stand abuse), then get the cheapest tablet thing you can find with a matching screen size (even second hand apple iPads are cheap enough to use as video screens) and pop them all together inside a conveniently sized white box possibly with a handle or two on it. Load suitable video on the tablet and you've got a generic electronic thingo which can be used for many different props in different settings radar, radio, spectrum analyser, scope, etc etc.
Or a cyanogen modded Nook Color
But if you do the thing with a 555 timer or Arduino, etc, to control the button contacts,
then after setting the thing, and saving as a default or auto, pull off all the knobs, squirt some glue in there, and put all the knobs back on.
Many front panels connect to the rest of the scope via a ribbon cable. Just disconnecting the ground would disable the controls.
By the sounds of it an old windows instrument set to boot on power being restored and with a looped video set to run in the start up folder is the simplest.
Late to the thread, but we do loan scopes and other equipment out to movie people for films. Most notably, Tony Stark apparently likes Agilent/Keysight equipment on the flying lab ship thingy. I just got one of my scopes back from a new Wahlberg movie, too. Generally directors don't really want labels showing, as it can be a distraction.
http://www.measurementest.com/2012/04/marvels-avengers-movie-test-and.html OP, if studios want equipment for a shoot, we have a contact person for that who's responsible for all the paperwork, etc. PM me and we can talk if you'd like. Our scopes do have a physical switch that will have the scope boot up automatically when it's connected to power.
Late to the thread, but we do loan scopes and other equipment out to movie people for films. Most notably, Tony Stark apparently likes Agilent/Keysight equipment on the flying lab ship thingy. I just got one of my scopes back from a new Wahlberg movie, too. Generally directors don't really want labels showing, as it can be a distraction.
http://www.measurementest.com/2012/04/marvels-avengers-movie-test-and.html
OP, if studios want equipment for a shoot, we have a contact person for that who's responsible for all the paperwork, etc. PM me and we can talk if you'd like. Our scopes do have a physical switch that will have the scope boot up automatically when it's connected to power.
Thanks for the offer but we're in different countries. You guys generally operate on a wholly different scale to us here in the UK. I've browsed the websites of just a few US prop houses & the sheer volume of stuiff they have is extraordinary. Like 400 server cabinets & vast amounts of other electronics.
I find it hard to believe that (eg) Apple pays for every single Apple laptop that appears on TV.
I find it hard to believe that Apple pays... taxes, they should pay.
Thanks for the offer but we're in different countries.
That shouldn't matter much, as I'm sure Keysight could arrange something through its UK subsidiary.
Mfgr sponsoring is, in my opinion, the best and least stressful option.
I have a Hantek MSO5102D. Despite the numbering difference, it's almost identical to the 5072P. It definitely does have a solid mechanical switch and will turn on normally from the mains supply. The P line ARE cost-reduced versions but that's mostly by putting small memory depths in them - i doubt they would have changed the power supply switch.
Some other versions in the range (with 'V' suffix) can play pre-recorded videos. They're normally held on an internal SD card but might also play them from the front socket.
One note on product placement - most digital scopes waste a bit of space on an onscreen logo. It's usually in a fixed location but it's a bit more annoying to cover with tape. They may also have a huge logo on boot-up, but there's a hack to replace the Hantek one with your own choice.
I have a Hantek MSO5102D. Despite the numbering difference, it's almost identical to the 5072P. It definitely does have a solid mechanical switch and will turn on normally from the mains supply. The P line ARE cost-reduced versions but that's mostly by putting small memory depths in them - i doubt they would have changed the power supply switch.
Some other versions in the range (with 'V' suffix) can play pre-recorded videos. They're normally held on an internal SD card but might also play them from the front socket.
One note on product placement - most digital scopes waste a bit of space on an onscreen logo. It's usually in a fixed location but it's a bit more annoying to cover with tape. They may also have a huge logo on boot-up, but there's a hack to replace the Hantek one with your own choice.
Thanks so much. And can it automatically restore previously saved attenuator, timebase & trigger etc settings?
There're big gaps between people who know tech and those who dont. So it depends on the audience for your movie. Its best to use products people rarely know about for props. Less people know about agilent or rohde and shwartz or even rigol than they do of apple. I also often see lenovo thinkpads used quite a lot. They are reliable laptops and less people know about them than other laptops around.
The way the props work are in 2 ways, decoration and active props. Decoration props are static and you can use broken or not working devices for it (perhaps as long as theres a screen or some blinky LED lights). A datacenter of blinky LED lights is considered techy to many.
active props need to be doing something. In some cases the prop is actually built for the scene and takes part in the scene (like the car for batman). In other cases it will just be part of the background. These would be doing something and require people with the skill in the respective area to set up.
In order to obtain the props its often best to negotiate a loan where you are sent the product temporarily and have to give it back when done. The only cost involve is the insurance, other than that you really dont pay a thing. Top gear is a big example of this as the cars are loaned to them and the top gear team only pays insurance. Other ways you can do is buy them 2nd hand or find bargains. Even if it is partially working or doesnt it can be a bargain prop. Other things you can do is use counterfeits which is very popular in movies involving destruction of cars. Quite often if an expensive looking car is wrecked in a series/movie it will be a counterfeit version of the real thing. If you can get them to give you the product for free that would be better.
In big budget films, the mistake often done is buying the actual prop and demanding money for the brand being on film and covering it when they refuse to pay. Infact refusing to pay is the right thing to do even if the brand named is taped or covered because they werent approached first regarding this before the film is made.
I suggest getting an oscilloscope with display capable of multiple colours and that imitate *phosphor*. Those features that show things to be multi dimensional and varying like there is a lot of detail going on are the best. You can measure something and record it with the scope and play it back without stuff connected to it.
Other things you can do is use counterfeits which is very popular in movies involving destruction of cars. Quite often if an expensive looking car is wrecked in a series/movie it will be a counterfeit version of the real thing.
They buy body panels from the car manufacturers and make fake cars with them using an adaptable chassis. It's still expensive, but not as expensive as wrecking real cars.
Now they want to do it all digitally:
http://www.topgear.com/car-news/top-gear-magazine/exclusive-video-meet-blackbird-rig-transforms-any-car