Ian Hegglun has published his Cube Law amplifier in Volume 8 and returned in Volume 13 with a CSD (Current Source Driven) output stage. Ian builds on several earlier publications to improve on the concept. He maintains a PDF addendum to his article(s) documenting his progress on further developments, insights and measurements. Please see also the Oops section on any corrections to the original article.
There is also a discussion thread on this subject at diyaudio.com.
This is one of those very rare occasions when something really new is proposed for audio power amplification - thank you Ian!