Wouldn't this be a simple incremental improvement--hold it by the seat post, for example? Every bike has one of those, and they are pretty much in the same place. You'd also need a pair of 'arms' to keep the front wheel from falling to the side, but they would only need to provide guidance, not support.
Hanging the bike by the seat post or better yet, any part of the frame would be great. The front wheel could be secured using a Velcro strap. With bicycle floating, maybe a better oppurtunity for higher density.
