Designer Amos Dudley has designed a 35mm film camera that is completely made with a 3D printer, the SLO 35mm Film Camera. All of the components including the lens are printable. Then lens and shutter system are modular so they may be re-printed without printing an entirely new camera body.
Got a 3D printer, and a hankering for a building your own camera? You can download the plans for the SLO 35mm Film Camera, here.