As I see it, we don't need "double barrel" printheads for support material and plastic, but rather a 3D printhead tool changer. 

This would allow a lot of different materials to be part of a single job.

I have an idea where a 3D Printhead slides onto the end mill via gravity, and then the plunger at the top comes down to both secure everything and to push the material out of the syringe.

Anyone with any thoughts on this?