Last checked (6/17) recently w/ Ruger parts there were no Stainless Single Six Bisley Hammers available, (Stainless Bisley Grip Frames either)they are somewhat hard to come by, very limited supply.
Blue steel one, Midway, Brownells, and I have a extra one of those right now too should you need it.
Midway also shows where you can special order a Stainless Hammer, I have never done this but Midway does buy alot of parts from Ruger and might have better luck, for the most part thier prices are good too.
The Hammer has to have the Bisley Hump taken off, I use a small die grinder to get the bulk off and finish w/ hand file, emery paper to 400 grit.
Re-blue the steel or just finish the stainless.
Tools would just be what you need to dis-assemble the gun.
Here is my 3, .32's, The shorty has the Bisley Hammer Mods as mentioned above.
I also just did 1/2 the .45 Vaquero combo and working on the other half right now.
Another project that happened a few years ago. Using the rare stainless Single Six Bisley Hammer. No hump removal required when you use the Bisley Grip Frame.