I guess I will respond to this 11 month old thread, even though rdb may have done something by now.
First of all, he ruled out the AR10 frame, which rules out superior choices such as the DPMS 6.5 Creedmoor.
Now, when you look at the regular AR platform, there is an option that I would prefer to the declining in popularity
25WSSM. I would look at the Grendel case, specifically the 6mmAR or the (Ackley)Turbo varient for an experienced reloader. Since we know that the 25WSSM loses alot of steam when coupled with the heavier bullets, it does not enjoy the power advantage of the 25-06 vs the 243. The 243 has higher BC bullets, but the 25-06 can push 115-120 bullets fast enough to overcome this at the ranges that either round is practical.
However, with the 6mmAR being able to push the 105 Berger with a BC of .556 to 2750 & the Turbo can go 2850 & change, the WSSM has nothing in ballistics over this round for any target/varmit situation, in fact it would be a little behind & I would put them on equal footing for Deer/Hogs.
All of this with brass that is gaining in popularity instead of losing popularity, less powder & bang, better quality brass & accuracy potential, the ability to use 6.8 SPC or Grendel Mags, & very importantly less stress on the upper.
Here's the scoop on the 6mmAR & Turbo:
http://6mmar.com/ &
http://6mmar.com/6mmAR_Turbo_40_Improved.html