I bought my son a lightfoot world traveler. It is built with the cyclone 500 watt 24 volt system. The bike itself is the most comfortble bike I have ever ridden. The 24 volt system is not the fastest however it is a very good assist system. With a 20 amp battery it does 17 miles very well. The world traveler is a old model Rod will still build. It is fast for a long wheel base bike. He has a new design out called the smoothie it is purpose built for the Bionx hub motor. I really liked my sons bike so I bought myself a ranger. Not assisted however the nicest bike I have ever owned.

http://www.lightfootcycles.com/bikes.php