These drives are very cool...I've been working to create a useful one for about three years.
I haven't released a unit for FRC because of the immense challenges.
I won't detail them here, but I will tell you that we have a "large" box of failed iterations.
I've attached a picture of a 400:1 unit with a 2.5" OD and an 8mm CIM input.
Here is a video....these are from May 2013.
http://youtu.be/tJoWlCDmaLg