At Maker Faire I made a point to check out the electric scooters created by MIT students and instructors in the school’s MITers hackerspace.
(Related: read MIT MechEng student and current instructor Charles Guan’s recap of his Maker Faire experience.)
One of the scooters that particularly caught my eye was Ben Katz’ sweet scooter whose design is inspired by the Radio Flyer trike. Ben designed the tricycle around a brushless Turnigy motor, visualized the trike in Sketchup, welded, and machined the frame, and added a 40v LiFePO4 battery, motor controller, and gearbox. It can theoretically reach a top speed of over 45 MPH!
Ben’s blog Build-Its has tons of information on the project if you’d care to tackle your own.