Your suggestion is spot on. After I measured the distance between the couch and tv yesterday, I had 12 1/2 feet.. I move it up a bit and it's 9 1/2 feet. I do have a steel column right behind the couch (one of three that supports the steel I beam) which will get boxed out and dry-walled to just fit a switch, receptacle, and Aux rear speaker jacks.
I ran a 2nd set of speaker wire to the column behind the couch in case the placement of where I am putting the rear surrounds now doesn't work out. I am not an A/V guru but I do research the stuff and browse some A/V forums. I'm am always open to suggestions and tips.
Rears will be mounted at about 6'3". The sides are 4' from the couch.
I had a small Polk RM95 series 5.1 "in a box" setup but now I have a bigger room so I am upgrading the speakers.
The TV is a Sony 52" LCD that I bought in 2008. If it dies, I will get a 60" Samsung. (fingers crossed. LOL)
My receiver is a Denon AVR-1913. I got that in late 2012.
The front speakers are going to be the Polk TSi400.
The center is the Polk CS20
Side and Rear I am still undecided.
My Sub is a Mirage 8" but I will probably upgrade that too.
I ran in-wall rated 14/2 speaker wire to all the locations. The A/V stand is 60" wide and 28" high. The center ch speaker will site on top of that and the TV will be mounted on the wall just above it.
I just got done insulating some of the ceiling tonight. About half way done. Mon and Tues we will be putting the rest of the drywall up on the ceiling and maybe get to the walls in the TV and Poker rooms.