You sure do like your MB Quart's eh?! I really have no experience with their home stuff, just car audio which I was always happy with. I know what you mean about devoting more attention to the LCR, if you look at my current equipment list you can see I have done pretty much exactly that. I also still subscribe to that theory, but I love my movies so I want very good surround performance as well.
I still have some time to change my mind about 10,000 more times, but I think if I was buying right now today I would go with the 7 Ascend speakers. I am slowly working on the wife to just give me free reign of the room though, and if that happens I may go a bit crazy
I still wouldnt blow the budget out of the water, but I would probably change to the EMPTek towers, larger center, and dipole/bipole sides, bookshelf surrounds, with two PB-2000's.
I am pretty set now on at least one PB-2000, but more than likely two. As much as I try to fight it I need ported subs. I like bass too much and the louder and lower, the better. Plus I need to be able to one up my friends of course! One has a PB12-NSD in a similar sized (but open) room, and another has a PB13-Ultra in a mansion where he needs at LEAST two. Even though he needs two or more, that Ultra is still unreal! I think two PB-2000's in my much smaller, much more closed off room would be able to take out the Ultra though
Speaking of subs, I know I can assign each output to be either the same, left and right, or front and rear. I am not positive how much more control over each I have, but since it is a .2 receiver, and they are assignable, I would assume I can do at least some.
Sean