For the money, I'm fond of the M-310 series.
Being the cheapskate I am, I went directly to the manufacturer of the action - Lawton.
Actions
The 8500 is the action used in the CheyTac M-310.
Bobby has a group buy going for $795 including the scope rail of your choice here:
8500 Lawton actions. - Sniper's Hide Forums
Have them barrel it for you, or use your favorite gunsmith. Add your 700 pattern trigger.
McMillan, Manners and Mcree all inlet for the 8500.
If you haven't already done so - look at the 375 CheyTac.