So this might be something like that:
http://users.tm.net/lapointe/Electrostatic_Motor.html
Right, then I guess it should run faster if the person to be tested does the "shuffle soles on carpet" thing? (assuming few do have a van-de-graaf generator at home)
This looks like a sound theory of operation. I don't think the ones in the videos are made of metal, though there might be a way around that.
I wonder if they have them at the woo store in town, maybe I can play with one for free...