My friend had a broken Canon zoom lens and I decided to have a little experiment. It took maybe about 3 hours to make the measurments and draw up the design in Solidworks. The printing took maybe 16 hours total for all the individual parts, couple parts had to be reprinted since my measurments were not as accurate as they should've been hehe.
It works, surprisingly:-P The back focus was pretty much right on and was able to get the image in pretty good focus. Biggest problem was the throw for both the zoom and focus ring is not as long as it should've been so I couldn't reach infinity with the focus or go past 100mm on zoom. Should be easy fix tho, if I can be bothered to actually do it:-P
There is no aperature ring, since the actual aperature leaf is burried deep in the internal housing. Not worth the time to make it accessable as it would require completely redesigning the internal housing and mechanics.