I have a Rock Creek pre fit coming from them. Call Russell and he will help you out. I buy the nut and lug from NSS. Just be sure that if any action work is done that the smith does not recut the action threads. If they do tell Russell the thread size as the barrell threads have to be recut to that size. If not, there should be no issues. There is a nice write up on the Savage forum where a 6BR was built with a R/C barrel.
I can't attest to their quality, but you might consider McGowen: <http://www.mcgowenoutlet.com/prefits/remage.html> There is also a McGowen Barrel Outlet but their website says they are still adding inventory: <http://www.mcgowenoutlet.com/prefits/remage.html>