Hex Kiwi Drive

[asid61]

That might be a tad fast even for 6 CIMs, because of brownouts. Apart from that, I really love this implementation.
Your CIMs appear to be bleeding into the bellypan.
Have you thought about using the Vex clamping gearboxes instead of custom? I like your implementation as it keeps this low to the ground, but it's something to think about.

EDIT: Missed the upper fame. As Jay said, adding some 2x1s or something with cuts to that they fit into the main rail and upper rail would be much more secure.