I've got a box of parts from when I was making a N64 portable. I got to about 65% complete and didn't finish because I wasn't happy with how the build quality was coming out. Even still, there's a good list of working stuff in here:
- PSOne portable screen
- N64 board that's been shrunk a bit in footprint
- Memory card
- Rumble pack
- RAM expander
- N64 controller button pieces/custom protoboard
- Gamecube controller parts (better joystick, smaller d-pad, start button)
- PS2 controller parts for better R & L buttons
- Ribbon-cable wired n64 cart port
Basically everything you'd need to make a portable N64 less the batteries. Could see a 3D printed case bringing it all together.