The text only LCD buttons from NKK cost about $100 each. I have no idea how much the video buttons would cost, needless to say they are too expensive to be seen even in broadcast shotboxes which cost thousands of pounds.
The ability to show thumbnails on a screen which matches the layout of a specific control surface would be the best solution. This wil be possible in resolume 5 with CITP - one could imagine a RaspberryPi communicating with resolume to provide a dynamic gui / thumbnail / preview screen which was matched to a physical control surface.
There is a lot to be said for combination touch screen / physical button controllers, look at pretty much any recent digital sound desk, or lighting console and it will likely feature a touch screen alongside its buttons and knobs.
I'd like to see a way to build function specific guis for touch screens so you could have colour pickers or corner pin effects control for example.