This is a simple 2-piece clamshell case that fits around the M12 type board camera on ebay which is sold as compatible with the Raspberry Pi (search for "raspberry camera board M12x0.5 lens"). It is different from and larger than the official R-Pi camera board, but it works in the same way and connects with the same 15-way flex cable. There is also a U-shaped bracket to allow pan and tilt motions.  You will probably want to ream out the holes with a 3 mm drill bit to make them round and ID = 3 mm.

All screws and nuts are M3, choose a suitable length. Four screws pass through the board and both top & bottom of the case. The screws going out either side of the case to the U-bracket have captive nuts on the outside, so the head is on the inside. This can work loose easily, so some locktite / superglue might help. SCAD file provided for modifications. The SCAD assembly also includes a model of the camera board itself + an example M12 lens.

Updated to v1.1: made the U about 2 mm deeper so the camera case can swivel through without hitting the top of the pan-axis screw.