Chris Patton was interviewed on the Water Fuel Museum radio show by James Robey on 3/11/2007. Patton claims that he had a team of engineers reproduce the Boyce design for a documentary he was making, and that the device had production at ~4X Faraday. At the time of the interview, Patton anticipated the movie would be released at the end of 2007. The show can be heard at
(Boyce starts at 31 min.)
Patton says that when he visited Boyce, another person brought over a Boyce-reproduction to demo for the camera. So there would appear to be at least two machines out there.
Patton comments that Boyce has released plenty of information to reproduce the device but that each device must be tuned for optimal performance.
KevinR