I can't help but to bounce this thread back to life. It's such interesting stuff. I've got ideas swirling around. Electro mechanical barista bot. I can't wait to start seeing these come to fruition.

Personally I would just replace the lever on a lever machine with a pneumatic piston, problem solved. Then, with some fancy engineering one could step up the game one peg further and make a water chamber before the group, which has and entry an exit solenoid, much like the cylinders in an otto engine, and then use the pneumatic pump to first draw a predetermined amount of water from the PID'ed boiler and then push it out into the group. It would require a lot of fancy electronics, but it would also be 99% temp stable and very exact since the water volume can be exactly calculated from the piston travel, which can be calculated from air flow, pressure and time.
The benefit of this design is also that it separates the water from the air, so any air compressor can be used.

This is kind of interesting. I live in Taiwan. Is there any way to contact Kevin Wu of Formosa Coffee Company?

One thing that surprises me is that, even though Taiwan is tea country, there is a large coffee-manufacturing segment here--mainly because there is just so much manufacturing here in general, and half the male population in the country have engineering degrees.