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.
There was a TV Show in England called "Tomorrows World" that had a prototype version featured in the mid 80's. However, it was a CRT based design which meant the tube neck stuck out in front of your face and made you look like Barry Manilow!