> I've also heard the statement that composting woody biomass could result in more energy release than combustion?
This is most likely true, because the biomass is nearly completely oxidized, whereas combustion releases some degree of soot, which is incomplete combustion. A two-step pyrolysis (make charcoal with open burn, then gasify that charcoal) is also very efficient.
Ive been thinking over how to apply this to rotary or auger based compposters. Perhaps a metal pipe wrapped in heat exchange tubing which is wrapped in insulation, with an auger and compost inside might work?