One name that comes instantly to mind is Del Whitman. He was THE barrel guy for Rigby (Paso Robles). He probably has more recent experience putting together barrels, including the brazing of the lumps, regulating etc than any single person in the US (not counting actual gun making factories, like CSMC) . Dels done some barrel work for me and the work was best quality.
The last price I heard for a brand new set of barrels, completely finished, from scratch....was north of 15K.
The numbers Dewey floated to me were $12-14K. That was a little more than a year ago.