Hello Dan,
Yes, we do claim distortion cancelation when our stereo amp, Musician III is used in fully balanced monoblock configuration.
There is no any proprietary design. None what so ever. Any (transistor) stereo amp can be configured the same into fully balanced monoblock and on paper will have distortion cancelation too and Distortion-free sound is glorious...as you noted.
In real life if you want distortions cancelation then these from right channel must be equial to these from left channel and subctracting you have zero. Simple? In order to have it your parts tolerance (on right and left channels) MUST (M-U-S-T) be very high - otherwise one can create even more distortion.
Also, amplifier in such configuration has double slew rate (same raise time...but one channel go to +Signal and another to -Signal is distance of 2x Signal), double bandwidth, entire power supply dedicated to one speaker instead of two as was in stereo etc.
NCore has good specs on the paper, so one can try...
Simon