sudomod

How doable would it be to use a GBA SP case with an RPi Zero? I would also like to include XY buttons, as well as a 3DS slider. I'm assuming this isn't an easy project, so I'd do something easier first to get some experience.

It's is very much difficult. Unless you want to have exposed circuitry you're going to need an all in one board complete with buttons and adafruit 1000c on the board, all in 75x75 mm. This may be SP fans lucky day, as I'm designing one right now. It's slated for launch this year, but I'm super hella broke and it will take time. The BW car screen (I think I got the wrong chipset too) fits so perfect in the SP I completely abandoned the DMG build to save a pi zero. In my experience very few PS1 games work with the zero w and anything higher is unplayable, as well as the 32x giving it massive trouble. Therefore I'm only including the original buttons, and adding X,Y. More details as it's built, but I'm going to start a thread for support. It's liable to cost $100, so bear in mind that that brings the total cost to higher than a used wii-u. Check said thread for more information.