kip, is it CPIO, or GPIO?
with very little money you can convert it to a zero delay usb, that will be compatible with all of the images you see here.
CPIO however, i am unfamiliar with .
the little white cards with blue, (looks almost reddish purple on my office monitor) lights on them ( 2 of them, 1 per player) in the image that all the wires hub at are the encoders, a kit of 2 encoders the usb cable, and the button wires can be had on amazon for about 18$ US and it is super easy to install, its virtually plug and play.
it would be a small amount of work up front, but it would allow you to run the images built and posted here, with easse, only needed to go through the controller program sequence in emulation station, on first boot.