In the meantime, I've decided to switch to a brushless DC outrunner motor from Hobby King.
It should be a lot more powerful then the hub motor and I can use it with the same controlled I had bought for my hub motor. I'm switching to a belt drive and redesigning the back of my scooter a little. My current wheels are a little small so I'm springing for some nice 8" wheels from electricscooterparts.com. I still need to finish the design of the mount and figure out how to build it, but I might jump ahead and order everything I need for the belt drive. Almost everything else can probably either come from around MIT or McMaster so it won't take as long. Hopefully I'll be zooming around with a motor in the next few weeks.