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.
Seems pretty cool, could it be done on a game boy advanced screen? I always liked them better then the SP and would have kept mine but the no lite, gay.
Would 2AA's be enough to power it? I could always mod some cool rechargeable battery into it too.
No, won't work, the hack mentioned is for back-light; the GBA needs frount lighting.
In saying this, I have it in mind at some point, to mount some super-bright white LED's behind and alongside the LCD (so they don't glare on the screen) and see if the resulting light gives good illumination on the screen without washing out the colours. It is very cheap to do this, you just need the very flat LED's (I have some). If you use 3v LED's you can run these off the GBA batteries, although you might have to put another switch in the GBA to turn them on or off.
Give it a go, if you don't like the result you can easily get your GBA back to the same state it was in before.
It has to do with the way the screen's designed. If it's anything like the Game Boy COlor screen, you won't see anything with a backlight. You would need something like the Afterburner kit, which would only give you a milky, blue-ish image like on the original SP.
Is it possible to transplant the GBA SP "Brighter screen" screen into an original GBA? I'm pretty sure that's a true backlight.