Picked up the structural parts from McMaster-Carr on Monday. Today, to my surprise, I received the RobotMarketplace.com order with the motors, wheels, and hubs.
After weighing the hubs, the current total weight estimate is at 2.56 pounds, not counting wires and screws. Not a bad place to be.
I'm also pondering adding a KITT-style Larson Scanner to the front... <evil grin>