Dremel Flex Shaft Mount for the RepRap PRotos, but should fit on any standard M4 50mm extruder mount.
Screw the Flex shaft in.
Mount it on the carriage.
For generating the gcode from images I'm using cad.py in a Windows Virtual Machine right now. If anyone knows a OS X tool that works out of the box like slic3r, hints in the comments are welcome.