If you like all that, one of these days I am going to sit down and
design a class D power amp that uses only one output device. I have the
concept, and I am sure I can do it in the analog domain, but it is not
easy. Also, if I want it to cover the full range for audio, it is going
to be a very very fast four quadrant triac. I don't know if they make
them fast enough yet, but that doesn't mean the circuit can't be
designed, it just can't be built.



You can already get class D amps in a single chip needing only a couple
of passive components to work. Why bother making one from scratch?