Have never really needed this kind of stuff until now, I just
know that there is an xtra called Enhancer xtra for shockwave and
projectors that adds gamepad and joystick support. You can test it
and maybe ask the guys there for other input devices.
Depending on how that dance pad communicates with the
computer, there are a couple other xtras that may work. Look at
for a serial Xtra and USB Xtra. You can probably grab the data
stream using something like that and write program around