Ooo, I like, I like. I've been working on an omnidrive platform on my VEX robot for a while, and I'll tell you, the programming is much more fun and bit more complicated than it seems at first. I recommend scaling the wheels to each other so you can get full power going forward or sideways, but not max out all the motors going diagonally. If you want a reference to what I mean, I've written a library and posted it to the VEX Forum code archive. It's written in WPILib for the older IFI controllers/VEX controller, but the concepts and equations are the same. It can be found
here.
Send videos, I love how these things move!