A ready-made platform is offered by Visionect - their dev kits for system integrators: https://www.visionect.com/development_kits . Meant for professional use and thus the price.
It works by using the display purely as a framebuffer, everything is rendered on server and sent over wifi/3g. It gets you amazing autonomy times and is easily powered by solar in outdoor installations.
Wow, those are really cool and pretty much what I had in mind. It's a shame that the prices are so... extravagant. I understand that they don't care about the hobby market, but it still sucks they don't have one for around $100-$150.
It works by using the display purely as a framebuffer, everything is rendered on server and sent over wifi/3g. It gets you amazing autonomy times and is easily powered by solar in outdoor installations.
disclaimer: founders are friends