Building a custom rifle, are we? I did the same thing a year ago - advertised for a used rifle but only really wanting a receiver. Nice receivers sell for within $40 of used rifles at gun shows, so both times I've had a rifle built, I started with a used Model 700.
I got real lucky on the last one - I found a Model 700BDL with the 1997-2001 "enhanced" (engraved) receiver and a detachable box magazine in .30-06 that had 10 rounds shot in it. The owner sold me just the barreled action, which I sent to McGowen Precision Barrels, who blueprinted the receiver and installed a 25" fluted stainless barrel in .280 Ackley Improved.
Good luck in your search. Don't overlook sites like GunsAmerica and GunBroker.