Some additions;
Maybe adding on-board computing as well? I've got a couple of old 1Ghz
single-board computers, or maybe we could go the Rasp Pi route. Either
way, making it more self-contained.
Also, since this is more of an industrial level machine, it feels a bit
of a bodge to use printed parts in the extruder. How about we get Billy
to cast up aluminium copies of the printed part in his bucketforge? The
3-in-1 is basically functional again, so finishing the parts doesn't
seem like it'd be a problem.
I like the idea of space-saving on the print head. Gives the option of
adding more nozzles at some point, and possibly increasing both speed &
accuracy due to lower inertial mass.