You're making me regret not picking up a supposedly dead original GB at Nexus the other day! It was only $10 .. it had no battery cover and looked like something you wouldn't want to touch!

It's amazing how much you can repair just by cleaning up stuff though - you should check out this YouTube channel, he has a heap of amazing repairs: https://www.youtube.com/user/lukemorse1.

What's wrong with the rubber contacts on that GBA? They look fine in the pic, if they're sticking that'd normally be fixed by a decent clean i think.