[derefr]

Dynamic instability? E.g., give the board some extra electromagnets near the edge, which "balance" the same way humans to, by constantly pulsing back and forth. When you want to move, you exaggerate one half of the pulse cycle.

[phkahler]

I think you're on to something. There's enough magnetic field there to levitate a couple hundred pounds. It you can shape that field electronically, or even by interposing the right kind of material, it might be possible to create some lateral force.