[wilsonmw04]

maybe i need to clarify my comment. (i forget i'm talking to detail oriented folks) The drive I suggested would no allow "drifting" as you would see in the OP's design. It would allow the 'bot to turn within it's own radius and have the power to push along one axis. Are there better ways to do this? Yes, 6-wheel rockers come to mind. Holonomic drives are a bad choice for the games that i have seen in FIRST. There is too much contact and pushing to be feasible.I'm just not a fan of being able to apply only 1/2 my power to one direction.
I have seen very well built machines, (Henrico Triad) who use a mechanum wheel based drives, have difficultly with this years game because they cannot hold their ground around the rack. Until FIRST creates a finesse game or changes the rules to reduce the contact, power will outperform agility every time.

To Bob: L33t was not lost on me, Pwn3d... hehe.