Interesting...the Hunter Perfect Balance Ceiling Fan...they use a control ring that the blades float on...this makes sense. It basically moves the center of rotation to match the center of mass. Not something you can do with a mower blade because it has to operate in the tight confines of a mower deck. http://perfectbalance.hunterfan.com/.../how-it-works/
They have a little video clip too but I can't get it to play all the way through on either of my computers for some reason.
Well, doesn't look like it's going to stop raining...guess I'll go run some errands.