Alan Harton, Single Action Service, in Houston, TX specializes in single action revolvers. I have my SBH at his shop right now to resolve a light primer strike problem. He can not only flute cylinders, but perform any level of repair and custom work. He showed me some of his work while I was there and it is perfection. Plus, he is a gentleman. Frankly, I didn't even ask price when I went to him, but his reputation is that he is reasonable. I certainly cannot speak for him, but he may give you a price over the phone since there shouldn't be any hidden issues with the work. I am now tempted to call him up to have the trigger guard rounded off while he has my revolver.
Gunblast.com did a good writeup on Alan at http://www.gunblast.com/AlanHarton.htm Check out the photo examples of the blown up Colt SSA where he not only replaced the missing topstrap, but perfectly matched the finish. Also go to photo galleries of his work at http://gallery.mac.com/aharton He doesn't describe anything, but the photos speak for themselves. There are phone numbers and email addresses for him in the article. A Google search will take you to other very good comments on him.