At long last, I'm releasing the Itty Bitty Double Extruder: http://www.thingiverse.com/thing:566329


LeftFront.jpgExplode2.jpg2014-11-24 21.46.23.jpg2014-11-25 00.28.55.jpg

Based on MakerFarm hobbed bolts, Hexagon hot ends and NEMA 14 motors, it's super-compact, with the hot ends on 20mm centers and the whole package narrower and lighter than the stock single extruder. I've included everything you need to mount the extruder on a MakerFarm i3v printer, with hot end cooling, print cooling and a servo Z probe all integrated into the system.

Many thanks to RobH2 for countless hours of prototype testing and feedback.

If there's interest, I can start another thread for discussion.