A new kit by MickGyver, the KTRL CD32, converts cheap SNES USB controllers to the Amiga CD32, complete with button remapping, auto-fire, memory, and more. Leon Kiriliuk posted some pictures of the kit on Twitter.
Source: http://eab.abime.net/showthread.php?t=85056
Purchase: http://www.amibay.com/showthread.php?101948-KTRL-CD32-PCBs-and-Components
Assembly Instructions: http://www.daemonbite.com/ktrl/ktrl-cd32.html