sanni, my concern with this design is that it doesn't account for the battery module.
sanni:
And finally, I thought of an alternative to the cartridge adapters: An expansion port.It's a little PCB that gets soldered to the underside of the Arduino and that duplicates all its ports so you can plug-in expansion modules.
Not sure if I should pursue this idea though since it looks complicated.
Have you considered creating a new design that is more modular? For example, one PCB for the aduino and interface (buttons, SD, screen, power, etc) and then another PCB with the connectors (SNES, N64, GBA, etc)? Or didn't you have an older revision that worked that way?
Regardless, this is still super cool and I'm excited to update mine.