I got tired of having to remove my Game Boy Player to get access to the SD card on my SD2SP2 port, so I made this SD card mount.
The SD card reader used here is: https://www.adafruit.com/product/254
The board width happens to be just right to fit snug in the top of the serial port slot, so it works great.
I originally made a dimensionally accurate replica of the original cover, but found it particularly difficult to print. I included it nonetheless if you prefer a more original look.
Later I realized that since I will only ever use this with the Game Boy Player, it didn't make sense to fuss with trying to print the clips, so I made a significantly simpler one that is desgned for 3D printing instead of injection molding. The Game Boy Player will simply hold it in place when screwed in.
Hardware used: 4x M2x12
STEP files included so you can remix.
Print instructions
The bottom edges of the Gamecube are rounded! This makes this part very difficult to print. I strongly recommend you print the simplified model and that you print it upright like shown. If you print it with the bottom facing down, your rounded corner will look terrible.

I also recommend you maximize variable layer height at the top so that it prints as rounded as possible. This gets a very good looking result.

Finally, I recommend turning ironing on for the top layer only. This will get you a very nice smooth finish. The result looks excellent; nearly indistinguishable from original hardware.

The author marked this model as their own original creation.