Krell models, their imitators and DIY clones are, technically speaking, class A but use several sophisticated forms of sliding/switching bias to do so with much less heat dissipatation.
I am rather surprised with your comment. The only Krells that have been widely cloned are the KSA50/100, neither of which have any bias trickery.
Not sure i ever heard of a sliding bias model being cloned, although someone, somewhere must have done it.
My amplifiers are two Audiolab 8000M mono amplifiers.
These can do very nicely with some recapping/parts upgrading at this stage. A friend recently did a complete overhaul on his TAG and seems ecstatic.