If you are interested in re-barreling to something in the 7mm persuasion, I would recommend checking out the following link:
7mm Cartridge Guide
The link will take you to a very thorough discussion of the pros and cons of various 7mm chamberings currently in use in 1000 yard competition.
Personally, I think your 270WSM would be a good place to start. If you are not already doing so, begin handloading for it. From there, shoot it until you burn the throat out of the barrel. By then, you should have enough experience to really take advantage of whatever cartridge you decide to re-barrel to.
My personal quest to become a true long range shooter is still in its infancy. However, I am quickly coming to the conclusion that money spent on practice will trump money spent on equipment until I have developed the skill to shoot my rifles to the limits of their capability.
I still have a long way to go...