Looks sharp! I like the gear-in-tube approach.
One alteration that may help you assemble it more easily, at the expense of more machining work: We used thin pieces of metal to retain the bearings in place in 2009. I'm not sure if they were riveted or we tapped the holes, but you can kinda see it at the top of the robot in
this full-res picture. Might be something to consider.