Ruger has made both 4 5/8" and 5 1/2" blued and stainless SBH's with the smaller Blackhawk grip frame. Of course, there were also the 7 1/2" SBH Hunters which were available with a SBH size gripframe, except with a rounded trigger guard profile.
Like you, I also find either the Dragoon or round profile SBH gripframes much more comfortable than the BH size gripframes.