I pulled the trigger and sent my money to NYCEWheels yesterday. I paid an extra $100 for the High Speed kit that's supposed to raise the limit 5mph. I believe that gives me a 385rpm motor. If I can maintain about 23mph on level ground (vice 20) that should suffice.
I intend to install on my cyclocross bike (700c wheels). The dropouts are only 132.5mm - so I'm hoping they can stretch 2.5mm for the wheel. Worst case may require a new frame.