Self-balancing scooters a.k.a. Hoverboards are a great source of parts for such a project. Their high torque, direct drive brushless motors can drive loads of 100 kg or more. In addition ...

[XenonJohn] wrote in to let us know about updates and a recent test drive of an Electric Self-Balancing One-wheeled ... constructed mainly from a Razor Scooter to this more polished-looking ...