You are correct. The sr-2 does not support i7's. It takes those outrageously expensive xeon's.
I would never settle for anything less then an x58.
As arc-angel said, "If money was no object" Why wouldn't you spend the extra $3500 and get an sr-2 with xeon's and still set up the quad sli which the sr-2 does support? Sure it's overkill, but if you had the income of a basketball all-star, why wouldn't you?
That's my dream build. But yes, the 2600k is a good little processor, but the frame rate gain is minimal. You get the great majority of your frames from your video card. Plus, I think the fact that they integrated a graphics processor inside a cpu is just for those who don't have a lot of money. Now, I had all the money in the world to throw into my build last year but ended up going with only a AR3E and a 980x (latest at the time, besides the

sr-2 and xeon bundle

). The build you mentioned is good, but if money is no concern.......

sorry for the long post, I write long ones.