I'm wondering if anyone else has any input on such an attempt.

Would/could the mixing stage happen on the table?
-if so what kind of speed would be required.

or

Perhaps a UV activated epoxy would be adaptable?

I am envisioning a jbweld type material for gear printing.

uv cure printers do exist, and the uv cure material price is the limiter here, it is very expensive.

look at fab@home project. they have experience with liquid print heads. i think reprap has paste extruders and concrete extruders. there is some research as patents are expiring into ink-jet and piezoelectric.

There is also a danger with mixing using single head and cure times solidifying inside the nozzle head. you would need a filler material to allow the 2 resins to keep shape and properly mix. such as paper clay and a 2 part epoxy from alumilite corp.