do you have a turntable?
check out the ms. pinky dev area:
http://mspinky.com/Developers.html
they really have a nice system, i would seriously consider helping to get you guys the discs and SDK if you would seriously entertain the idea of integratin it.. I have spoken to them before and they are super cool, maybe they'd be willing to work something out..
i have the system and when used (with grid, or the included ms. pinky apps) i can say honestly that there is
no other control surface i have liked as much for altering the timeline of clips. it feels really smooth and natural. prolly cause you can go from full motion to scratch or subtle shifts without any jerkiness. In M8 now to video scratch with say a midi slider it is hard because you really have to pause the clip for it to feel like a fluid scratch.. but then when you want to let go and have it keep going you need to start it again, which can result it a lag or jerk as it is hard to time precisely..
one of the reasons i think ms. pinky's IWS is so fluid is cause there is actually a spinning disc that is controlling the timeline, even when you are not touching it..