I have, those are awesome. If you get some, I recommend calling in to the support line. Say you have an sensitivity issue, and the will send you the hardware and software to hook it up to the PC and adjust the sensitivity to each pad. Pretty cool.....
or use this link... http://www.redoctanegames.com/Warranty/USA/ you do not need a reciept to get the cable. I got one and don't even have GH yet.