Team 461 has been prototyping an omni-directional drive train concept we call Jump Drive. It switches between mecanum wheels and traction wheels to allow omnidirectional movement and also pushing power (similar to 148's "nonadrive"). We began building it in the Fall of 2009 but were only just able to complete it and get video.
Hope you enjoy it and please let us know what you think.
Video:
http://www.youtube.com/watch?v=uEUIshtjbe4
Pictures:
http://boilerinvasion.org/index.php?...2_itemId=24653