I'm in the same (almost) situation. I have a Colt 1909 in .45 Colt (same gun except in .45 Colt), it's been refinished years ago and has a sewer-pipe barrel. I picked up a new 'old' stock' 1917 barrel, want it chopped to 4.5 inches (one of the New Service standard lengths), have a new front sight put on, and mounted to the gun.
Called Turnbull, nice fellow called me back and said they won't do any barrel work on a New Service but if I ever want it blued or engraved they would give me a quote.
Called Colt. They don't work on their revolvers at all and suggested Grant Cunningham.
Called Cunningham, he is retired and referred me to Frank Glenn. Frank Glenn is backlogged.
Single-Actions forum referred me to Andy Horvath but he doesn't used a website. At all. Called his number, got no answer.
Thinking about finding a lathe, buying the end cutters and forcing cone cutters and doing it my damn self.