"So this means that you could have an Atari on a SD Card and an Amiga or C64 on others?"
Yes, absolutely. The FPGAARCADE board goes a step further and has a boot menu which allows you to pick a "platform", so it can be PACMAN, AMIGA, ATARIST, VIC20 etc etc (assuming you have the FPGA binaries for these platforms). I will try and back-port the AtariST code to the Minimig board when it is finished, but there a quite a lot of differences in the board.
My board also uses an AVR but it may be possible to port the firmware to the MiniMig PIC.
/Mike
