Anyone have any ideas for modding these cases for Game Gear? I have a pretty small GG library and I'm thinking that some careful cuts would keep the carts in place using the GB walls as supports. Just not sure where would be best...
There's no quick and easy way. You'd have to cut about 3/4 of the support/clips out before they'd even fit, then you'd need to devise something to hold them in place 
Not necessarily, if you don't care about it being centered. I think it can be done with a few simple cuts/clips and little or no additions to hold it in place. Here's a couple options I came up with.
Red is what to cut, black is put something there to keep it in place, mockup is approximate size based on my tests:



Obviously his GG cases will be awesome and I'll be getting them whenever he does make them. But he he's likely making his NES, SNES, N64, Genesis, EA/32X Genesis and possibly double-GB cases before that. Besides, for now I currently only own 9 GG games, and I'm going to end up with several extra GB cases with my next batch, so I figure - why not? It's a lot cleaner and a lot less work than chopping up DS cases.