The 7mm-08 is one of my favorite whitetail cartridges out to 200 yards. Sure, it can be used at further ranges, but I don't shoot further than 200 yards so I really can't give you first hand experience with such long shots.
As for all the guns you mentioned, your best bet is the Remington Mountain LSS. One heck of a gun. I just love it. I would forget about the M7 because it only has a 20" barrel, and I like barrels of at least 22" on standard cartridges, and 24" or better on magnums.
Zachary