Actually not to bust any of you guys bubble, but I rember a guy on Tech TV (now G4TV) put a reall Atari into a hand held. He had a website and everything. He cut the board into 3 different peices and ran wires where they needed to be connected. He did say he trashed a few MoBo's in the process tho. But hey it was a cheap test. He even went as far as to make his own cases for them.
With a little search I found the guy, hes been busy, how about a portable PS2
Or the atari
Here is his offical website, he has built quite a few of them using different systemswww.benheck.com
So you see there, dont let somebody say you cant do something. If you think it can be done then try it. I somebody told the guy who wanted to build the first modchip was told it would not work. Well we all know the answer to that story.