Mosfet mist?

I think you are right and a hybrid tube amp would be a good idea for home theater. It would have no output transformers which you like. So lets get cracking.

I personally like the more tube like sonic signature of mosfets vs bipolars. I recently acquired a Counterpoint SA100 rebuilt by Greenstreet Audio with Exicon mosfets and with some tweaking and replacing of the coupling caps @ the tube gain stage I'd say there's hardly any mist I could detect and all there is is music.
I currently own Vac Phi 70 mono, Counterpoint Altavista NP220PG, NP100PG, and some heavily modded/rebuilt tube amps.
Mosfet amps are given a bum-rap by designers not going all out to do them justice by using up to par components in the gain and driver stage. Fix all the problems upstream and use modern mosfets that are less lossy and you wont need to burn money with power tubes (esp. those Sovteks passed off as so-called whatever brand reissues)

Lamm does ok with their mosfet based hybrids.

Some early mosfets had a slow decay , it gave them a slow unclean sound , maybe thats where the term came from .

Sounds like the name for a pop wine beverage. It's mythological. I used to own a bipolar amp from Bryston and have been running a JEFT/MOSFET amp from Hafler for no less than 16 years. No "mist" has been detected, but if I ever got back into reading one of the audiophile media mags they might incite this angst in me. Toss this one to Peter Aczel the Audio Critic and watch him go ballistic!