I’ve been working on this drive-train CAD for about 2 months now, and it’s basically finished. It doesn’t have all the fasteners, or a gearbox or electronics, however.
Dimensions are 27 wide by 28 long, for a frame perimeter of 110". The wheelbase is 21.8 long by 24.6
wide. Its using standard 1" wide vex traction wheels with hex versahubs. Total weight without fasteners is around 37lbs. It has integrated bumper mounts on the drive sides. The bumper has angle aluminum in the corners that slide into the corner posts of the drive train to restrict X and Y movement, and then spring-loaded latches slip on to hooks on the bumper and hold it on (Z movement). The Drive sides are non-integral to the strucutre of the drive-base so they can be taken out for maintenance without taking off the superstructure. Below is CAD for anyone who wants it.