If you're making a portable you probably need something to watch it on. (Unless you want to guess what's happening in the game, but I wouldn't advise that) Anyway, this forum is your "Hacking a pocket TV/screen" one-stop solution. Share your experiences and knowledge here.
I'm tryin to hack a Mintek screen now. The screen on mine is the same model # as the PSone screens use. If you get one, pop the screen case and take a look at the markings on the controller IC and try to track down the factory datasheet on it. That's where I started and it'll tell you if it supports NTSC, PAL, RGB input type, etc...