I know I"m a bit off topic here since you want to buy prebuilt and pedal, but here is a new scooter coming out I saw. From what I have read they are the best.
http://www.superscootersales.com/?pa...&product_id=60
I'm with Metallover, get one of these motors
http://www.thesuperkids.com/hi2hicumo.html
slap it on your bike with a 5k thumb throttle for 50 bucks (no sep controllers needed)
and 7S of the 5k 20C turnigys (dont do 8s it frys the motor, I know this)
as many as you need to get the distance.
I bought an old currie phat flyer scooter for 50 bucks that I upgraded with the turnigys, kept the stock 300w motor on 8S and it just flys. 22mph and I weight 160 pounds. Since the lipos are so small compared to the standard lead acid batteries you can fit just about as many as you want.
I think the wattages are deceiving for those motors as they are big as rocks, but only rated at 300 or 400watts.