To solve the control plate on/off issue how about this idea:
All new Dual pickup Stingrays come with no control plate, but a control plate is included with your bass. The control plate has no screwholes (just holes for the knobs), and on one side has a 3M Sticky stuff on one side covered by wax paper (or whatever they use to cover it before use). All you do if you want a control plate is remove the knobs, take the paper off the backside of the control plate, put it over the knobs with the sticky side on the body, put the knobs back on and BAM! A beautiful 2 Pickup control-plated monster!
How 'bout it?