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.
Best info I can seem to find on it is here and here. This could be worth a look as well, though a direct link inside that reference doesn't seem to be of any use in all honesty.