Just a blue sky thought... Would this even be technically possible?
Imagine a CNC laser, where the laser was (1) capable of cutting
through the fiberglass, and (2) the right wavelength to expose a
photomask. Now, in theory, you could paint/adhere the mask to the
board, CNC "expose" it, etch, paint another mask, expose it for solder
mask, then laser drill each hole (having removed the copper during
etch).
Since it's always the same machine, the copper, mask, and drills
should all line up, and the accuracy would depend only on the CNC
accuracy and the size of the laser beam.
Imagine a CNC laser, where the laser was (1) capable of cutting
through the fiberglass, and (2) the right wavelength to expose a
photomask. Now, in theory, you could paint/adhere the mask to the
board, CNC "expose" it, etch, paint another mask, expose it for solder
mask, then laser drill each hole (having removed the copper during
etch).
Since it's always the same machine, the copper, mask, and drills
should all line up, and the accuracy would depend only on the CNC
accuracy and the size of the laser beam.