i’m using an m-audio sustain pedal, made for keyboards, connected via a stereo 1/4″ to 1/8″ adapter. it works great, and the pedal is WAY sturdier than the included rock band pedal. in the video i have it hooked up through a headphone splitter, and that works for double pedal action with the included rock band pedal, but holding one pedal down will not allow the other to trigger. i got this sustain pedal from amazon.com for around $13, but you could probably get one at any music store as well. the needed action is on/off, so a sustain pedal works great, don’t try an expression pedal.
at the end you get a little beatmania iidx action. if you like rock band or any other rhythm game, you should check out the original: beatmania iidx. it’s super fun, but kinda hard to get into since it’s mostly japanese. look it up.