Would the ASCII controller (http://www.amazon.com/Nintendo-GameCube-ASCII-Keyboard-Controller/dp/B0000694RM) work on PC through the Mayflash adapter? Or is there some other way this could work?
Apparently you can use this adapter but you have to buy two of them:
http://raphnet.com/products/gc_n64_usb/index.php
This is another adapter, not the v2 discontinued.