Anyone have any suggestions?
A few and some you may have not considered.
I don't mind connecting the instrument up to my PC, then displaying the PC screen on the projector but haven't found software that seems up to the task.
The trick is get equipment with an inbuilt webserver that via a LAN connection and a browser tab you connect to the instrument via its IP and then use the display/remote control feature to view it and/or port the browser tab image to another display device in near to real time. No SW or special tricks required other than pointing the browser to the instruments IP address.
A rough and ready example:
https://youtu.be/W30AqcDQL18I'm also interested in any recommendations regarding particular scopes and spectrum analyzers that have a video output port.
As pointed out above a HDMI or VGA port is not required if you use a LAN connection and an instrument with an inbuilt webrowser.
From the Siglent stable, instruments with webrowsers that can provide LAN connection remote display/control and video examples of 'how to':
Scopes:
SDS5000X series
SDS2000X-E series (only available in 2ch models)
SDS1004X-E models
https://youtu.be/Cxh_Liay09ESpectrum analyser
SVA1015X
https://youtu.be/AG3xw8jvu6ISDS1004X-E models, yes from $499 a 100 MHz 4ch DSO that makes porting to a screen easy.