I am here! Can't talk long as Law & Order is on soon...
This is actually a cool idea, and something I've considered in the past. My idea was to basically make a MAME portable using a Micro ATX form factor, CompactFlash drive and built-in controls. Running Windows 98 or something that would fit on a Flash card.
Joe is right, most of those "micro boards" output composite video, S-video, all sorts of stuff. I know of a place to get a 7" widescreen TFT for around $150.
I think the biggest problem would be the power supply and getting the right PC guts that fit. The Micro ATX's, for example, required all the usually PC motherboard voltages such as +5, -5, +3.3, +12 and -12. That'd be a pain to get out of a battery (and explains why PC power supplies are so big) If a board just had a few voltages it's a lot more do-able.
Joe, if you're really interested in this, and can handle the software portion plsu buy the hardware we'd need, I'd be willing to help. I think people would get a kick out of it, especially "The English Patient" fans.
Email me at
benjamin.heckendorn@gmail.com if you'd like to discuss.