I do find it intersting on the differnt ideas for omni drive wheels or track. In 2004 we used omni drive wheels and was able to climb the stairs of that game. The wheel segments acted like teath to grab the steps to climb. I also came up with a omni track design, My idea was to design the track like beads on a pearl necklace and the drive sprockets looked like paddle wheels with each V shaped paddle would come down between the beads and the weight would be on the axle thus alowing for the rollers to turn free. The steel axles would have enlaged ends that would snap into the holes of the Plastic balls. You than can Paint rubber (avalable at Granger) on the wheels for traction. This does not sound that heavy but a lot of work. check our web site for all the wheels we Painted.
http://team1322.org/robotics_04-05.htm also check the tech tips for our omni wheel designs