Bolo,
It's just supposition on my part, actually. Since the Yamahiko's are a Japaneese product, I don't actually know if they have U.S. pattens or not for their transducers. On the other hand, at least as far as I know, they were the first to mount transducers inside bridge adjusters many years before the Full Circle arrived on the market.
There was also a rumor floating around several years ago that the original "Blender" unit was designed for Bela Fleck, but not developed as a "production unit" until Fishman brought it to the market. But, once agian it's just a rumor. Incidentally, the Yamahiko dual sensor system costs $600.00 so it's up there with the Schertler Dyna B.
Ric