I have a reprap(pro) huxley with melzi and I would really like to be able to use dual extruders, to use PVA supports, t'he heated bed unused connector seems like a great idea! For the heatsink, a cut old CPU heatsink might be enough, I think the marlin software does support dual extruders. If It can't, we could use a slave melzi or an arduino to control de 2nd extruder.by ReDeathRay - Huxley