Hi Matt, Welcome.
You should look at Nick's build thread and peruse some of the other threads.
It sounds like you've already done a fair amount of analysis. I'd offer up only a couple observations.
First, I wouldn't let the impedance of the M80/VP180 dissuade you. Those are Axiom's "ultimate" HT speakers and that is a pretty big room. If you can swing the extra money and extra space, well, you know. You can always add amplification later if you find that your receiver doesn't power them as loudly as you'd like, but I very seriously doubt that happening.
That being said, I think you'll love the VP160/M60 combination and it's probably more than plenty.
Second, I'm glad to see you're planning for a second sub. Again, that's a big room. I'd also wire for multiple possible sub locations. I'd really recommend two subs, and maybe the VTF-3 or similar. You can spend an ungodly amount of money on subs. Hsu presents a good value, as does SVS and many other companies including Axiom. I really think - in view of your overall plan and room size - you're a little undercapitalized on subwoofer capacity for movies.
Because the QS8's are so good, I didn't get a cost-proportionate thrill going from 5.1 to 7.1 in my room.
Get plenty of electrical circuits in there.
HAVE FUN!
