Great design!

I re-scaled it uniformly x 1.2 to account for the tolerances on my printer, and have slightly wider lens opening, in case I don't do a great job gluing it :)

Turned out awesome, very sturdy and practical.

Pictured here is the focus ring on Raspberry Pi camera attached to MP Select Mini using a mount I designed:
http://www.thingiverse.com/thing:2267182