Build the Surgeon in 308. In a year or so buy another Surgeon, build in 260, but look at 6.5-284 before you do. Surgeon has a larger actions that will take 338 Lapua, build one of those down the road. Repeat process as often as you can. Check out the 5R barels here too.
http://www.bartleinbarrels.com/
There really isn't anything like having a rifle built the way YOU want, not what some company makes for the masses. It is a terrible addition (custom rifles), I could help you by taking that Surgeon off your hands. I may even have a Remy sitting around that would be good trade stock.
You had to get me thinking of the 6.5-284 again didn't you! LOL
I really don't think I want to afford three custom rifles to be honest...so...would I be better off getting a surgeon long action and chambering for a 6.5-284 or a straight 284 for higher bc bullets and longer barrel life? For hunting I think that is a much better deal, and the ballistics are way better on both cartridges than a .308 with better bullet seleciton...