Now that the droid is mostly done, I've been working on a third dome. Like the R4 dome I've already made, the clear R3 dome can be installed in seconds to my droid body. The rockler bearing holes are the same, so the dome just slides on and off.
I am using an aluminum base ring on my R3, so I had to do some extra work. The normal base ring has a plate to mount stuff on and holes for the bearing. Since the aluminum ring is empty, I had to make a base plate and include rockler bearing holes.
I've put pictures over on Astromech.net: http://astromech.net/forums/showthread.php?t=1245&page=2