Yes I am not so worried about the subwoofer. I know I would have to have a MONSTER of an amp for that one. And having plenty of headroom for dynamics n a movie and Crest factor in music has always had me wanting much more than is probably needed.
BUT when building these amps I dont want to build something that is never going to happen because of parts costs and complexity. While it would be fun to build a XA1000, lol, its never going to happen. I know it wont because of other reasons but that was just my point.
BUT back to your point I would be about 2.5m - 4m away when watching movies. BUT I dont listen at reference level so 30watts may do it. Or I just double that to make sure I do have enough. And I will have a pair of 18's that will have to have a amplifier channel each going to them or mono. Those re about 2.5meters away. And I will be adding another single 21" down the road. BUT I dont want to talk about speakers just getting power to them is all.
F5Turbo sounded like an option but it seems like all designs can be ramped up for whatever output.