I'm starting to put this all together. Lots of little ideas that just might work.
It all started with the stand and then the room dimensions, being equidistant,
and the display distance.
So this might not make sense but here it goes...
24" tall x 96" wide x 36" deep cabinet with built in subs at each end.
The stand would sit 12' from the front wall in a 8'x24'x36 room with the sweet spot 12' from the center channel.
The screen would then be fixed on the front wall or would be the wall itself. The projector would be behind the built in center.
Two ADA1500 sit below the center, the power center and reciever below the projector. IR repeaters and my Galaxy Note control the works.

The viewer will look between the towers and over the cabinet at the 120"+ screen.
When not using the screen the towers will have room to work their magic. No furniture inline with them, only the main seating position. And...I went from a party of 3 to 9 with piles of room to spare.
The towers 12' apart, with all but the towers 12' from the main seats.
The towers in line with the cabinet an thus slightly farther away.

Its all just wishfull thinking but it looks good on paper.

I'm sure something here won't work. Please feel free to pick it apart.

$500 bucks is a really great price for a custom stand of the size you will need. I'd say jump on it if it looks good in person. Unless he is making it out of pressboard and duct tape, he is obviously just building for the love of building.

Speaking from my limited experience, people just don't realize how long stuff takes when they ask "hey, could you build me one of those?" I spent about 6 hours yesterday just making a yo-yo for a friend at work.

$500 would have been a nice price.
I'm pretty sure I'll need to site build this one, unless axiom was willing to build it...
Now picture that. 4-12" subs, 2 facing forward two to the rear, clean look, nothing on top,hand sanded no gloss rosewood finish.
I can see this is going to take a lot more homework.

This one's only 24" deep. Think I can get it to 22"x22"x86". Possibly 84".
I'd want 2.
1 for up front and 1 for behind the main chairs.

I'd turn the EP500's so the face was clean.
Hopefully having the subs facing my towers won't matter.
I might have to think about running 6.1 with 4 subs.
2 VP180's, 4 M80's and 4 EP500's.
I really like how that sounds.

I've never had 6.1 surround. Anyone care to comment on the pros and cons?
I'd assume a 7.1 signal can be changed.

I've got 6.1 and if there's something coming out of the surrounds, 5 channel or 7 channel, I have something coming out of the single rear channel.

How does the sound compare to 7.1? It should be roughly equivalent and could be adjusted at the Receiver. Would this be a fair assumption?