Hi Drunkpenguin,
Welcome to the family. Like Peng, I too recently migrated to the X4400H (see
Denon AVR-X4400H - Initial Setup ) , and although I keep getting pulled away from my new toy => by work and family issues (like an urgent bathroom renovation),the more I play with it, the better I like it.
I too couldn't find anywhere nearby to really listen to a decent immersive sound setup. So being a little crazy, I just went for it. (I was also a 3D TV early adopter, and we all know haw that's going...
)
I have gone full out on speakers => 7 at ear level, 4 in ceiling, and 2 subs. (Although the current plan is to replace my aged front 3 with HSU CCB-8s). But of course without an extra two channel amplifier hooked into the system, I can't drive them all simultaneously. My room is about 20' x 16.5' (see first post in link above as it's somewhat "irregular"). So far I have it set up as a 5.2.4 (the Rear Surrounds aren't being driven) and it seems fine.
I wonder if adding the last 2 channels will be very noticable. In my room, I'm thinking they may not, as so far the rear Atmos speakers are hardly noticeable, although my sample size is too small to make that judgment yet.
I look forward to reading about your X4400H install and experiences. So keep on Posting.