Today we are working on printing and mounting a GoPro mount for the Original prusa I3 MK2 I designed based on some other Go Pro mounts.
The model can be found at http://www.thingiverse.com/thing:2185925
You will need a 12mm M3 screw to mount it to the printer, it will screw directly into the plastic so you do not need a nut.
For mounting the GoPro you will need a M5 nut, that can be inserted in the mount. Make sure you cleanup your support properly before inserting the nut.