The glass and hairspray technique is something used previously. As a result, I have a piece of glass. The current setup is the metal original bed with the glass on top, and painters tape holding down the glass.
As mentioned, the item I saw about two-years-ago was a rubber (?) flexible sheet. if I remember correctly, a strip of magnetized metal gets taped to the bed, and this sheet sticks to it using magnets. After a print is complete, the entire rubber sheet lifts off and you can peel it away from the print, and then reapply the rubber sheet.
It looked quite useful, but at the time painters tape seemed to do the trick.
My Anet has a front and rear bracket mounted to it preventing (or reducing frame bending). If I remember correctly, the design shows to mount these utilizing the threaded rod, however, I have a piece of wood (clear stained) as a base and screwed the printed brackets into the wood. Also, the threaded rod has four brackets holding them down to the wood base as well. For some reason I remember using t-nuts, but, either way, the printer is mounted quite tight to the wood base (maybe 3/8" wood - not plywood - some sort of quality stuff I think). It even has the brackets for the upper part to reduce wobbling.
Basically my printer can be spun on every axis in the middle of a room and (hopefully) not see a shift in the frame - at least this is the image I have due to the amount of effort I put into making it sturdy.

The big issues are bed leveling (I absolutely agree that the BL Touch is a great improvement - I just never got around to adding it) and belt tension. Otherwise, I've taken into account all the mounting, reduced friction everywhere I could, etc...
I could be wrong, but believe due to the lack of features I care about (open thermistors shut down is the first feature I care about), I'm able to fit the BL Touch and standard features into the amount of memory available - you're correct though - it's awfully close to running out of room.
The personal issue I had was (as mentioned) felt I was dumping more time/money into the printer and using it to test upgrades rather than just buying some $2k unit that wouldn't need any (or much) upgrades.
My plan was to get a new PC, expand my interests on the mechanical side (I've taken on more interests doing 2D drawings and 3D designs), and maybe then upgrade to a new printer. My hurtles are that in order to transfer my extensive amount of software that I "obtained" years back when it was easier to "obtain", I'd need to "buy" updated versions. If I use a virtual XP system (or run two PCs) so I can still use my software, then I use old software that I can't use new files in. An example is say Altium. I can't take a new Altium file and have it open in a decade old version (or maybe I can, but just using an example).
Normally I use my work laptop for stuff and my XP to bang around. It's getting more ridiculous though to work around such issues as I just experienced with this knob where I have very limited options on taking a STL file and tweaking it or working with someone who has a CAD file who can share it so I can tweak it. My work laptop is limited on what I can do since I can't install anything and certain sites are blocked, but my XP is limited for obvious reasons. Also, I just dread new computers. Having to work through 30-day trial software, the quirks, installing codecs, etc... Wish XP would have just remained the OS forever.
