This started because I have several C-mount style lenses.  I say “style” because they didn't work with a proper C-mount camera.  They didn't use the standard distance from the c-mount to the image sensor.   I use cheap web cameras to supply the sensor.  The sensor is much smaller than what the lenses were designed for which degrades the image and gives a telephoto  effect.  

No supports are needed.  The camera body, with the c-mount threads, should be printed at 0.1 or less layer height. The threads for the focal plane adjustment are quite loose intentionally.  In use, they should be wrapped with a heavy layer of teflon tape.  This gives a smooth action that still stays put.  The alternative backs are attached with 2 10mm M3 screws into heat set inserts in the body.  The tripod mount uses a captive ¼" nut.  Set a pause at the last layer with a hex opening and just drop in the nut and resume.

It should be easy to modify for different camera boards by cutting out a different recess and, if necessary, gluing it in place.  Even better, modify the onshape design. The provided model uses a camera board that is 30x25mm and press fits.  It has a removable lens so you don't have to tear apart a web camera.  I have done both and either one works, but removing the lens can be very delicate.  The camera shown here uses this currently available from Amazon.

One of the photos shows my smallest lens and largest lens.  The large lens sports an earlier version of the camera.   The example photo comes from the small lens.  The large one works but takes two hands to support and will have to wait for a tripod attachment for the lens.