Jimmy made a custom 1/2 cock Super Blackhawk hammer for my 45 Colt BH, and did a slick action/trigger job on it. He's a nice guy and does good work.http://www.cowboygunworks.com/index.html
Here it is, I met Jim at a SASS match several years ago and handled a couple of his Ruger’s. He might do a Blackhawk.
Give him a call, great gunsmith