Howdy
From one I understand, while some stainless steels, mainly the Austenitic ones, can be surface finished various colors electrolytically, it is not really practical for a firearm. Such finishes are not very durable, and once scratched, the base color of the stainless will show right through. And I doubt the blue available will much look like a traditional gun blue. You can't touch it up either, like you can with cold blue on a blued surface.
Anodizing is also possible, but it is not as rugged as anodizing on aluminum. Plus, with anodizing, I doubt if you will get a mirror finish, I believe it will always be a matte finish.
The idea behind the Stainless Vaqueros, when Ruger first introduce the highly polished version was it was a fair approximation of an old fashioned Nickel Plated finish. That has always worked for me.
My 1860 Army pistols are blue, and look like a brand new pair of blued pistols. I don't see the need for Stainless, I shoot Black Powder with both blued and Stainless guns.