I've always hoped for a deck emulation mode in Media Express to allow any device to control it over RS422. This wouldn't be too much harder to do.
However, for less than the cost of that system, you could put an AJA KiPro Quad on the back of the camera and have a completely mobile, non-tethered ProRes4444 capture.
http://www.aja.com/en/products/ki-pro-quad/#overview