A remix of the pi 2 camera mount I liked by Mirar found at https://www.thingiverse.com/thing:3183893.
I borrowed the Prusa mounting arm and camera housing (trimmed down a little) from this project and added an adjustable/extendable mount that could be removed and used freestanding on a base.
Attached are the Fusion 360 files if you want to tinker.
Prusa arm is printed in ABS as it hangs off the heated bed.
The upper section (cam mount pt3) is printed with supports for the external overhang, all the rest - no supports. PLA / 0.15mm.
Camera body glues to the top supporting plate. Mirar's design for the body is perfect/snug fit so insert your pi camera first before attaching.
Joint screw holes are a nominal 2mm, I widened them out a little to make use of the spare screws that come with the Prusa.
Cam mount pt5 is an extension tube, use as many or none as your like. Design has zero tolerances factored in so the inner tube can be sanded a little for a decent friction fit.
Supports on one part as detailed above.
Fusion 360 / digital caliper guage