[asid61]

Now that I've seen the CAD:
1. Why chains over belt for the first stage? That's going to be running at a rather high speed.
2. You might have trouble with the round spacers on the bottom of the casterboxes, because you are using screws on both sides. Why not either use a screw + nut or hex standoffs so you can get a wrench on it?
3. Why live axles over dead axle on the last stage, and why 3/8" bearings instead of just thunderhex bearings? It saves some machining imo.
4. Are you sure that the casterbox won't hit the VP output shaft when it turns? I can't tell from the model.
Apart from that it looks good.