This paddle turned up at my work, I thought it might be of interest, or somebody might know who made it..
It has a motor in the bulbous part of the paddle, a simple thumb switch in the handle and can be connected to a car battery. The prop is a model aircraft variety and seems to have a limited slip clutch to avoid damage.
72V Crooza scooter, converted to lifepo4 24AH 24S2P Headway, Lyen 18FET controller, 47mph
72V E-max 110S converted to lifepo4 A123 100AH 24S5P, Sabvoton 72150 controller, 49mph