Excellent! So with the part William made and that particular setup you can have the feeder bowden tubes any length? I'm trying to visualize how I would want to set it all up in my enclosure and am envisioning mounting the steppers to the ceiling of the enclosure rather than the frame since the spools are fed from above. But in doing that it would mean the tubes from the steppers to the junction would be 4-6" above the top frame. Would that be a problem?

This looks like a really good solution. I had wondered about the Micro Swiss DD setup with the 3DC but this seems to be the part that it was missing. One thing I'm curious about - since DD setups are sensitive to vibrations which can result in ringing or other artifacts on the prints, have you noticed anything like that with the extra weight on the extruder?