I have searched extensively and have found none. However, I have added a #8 Tyler T-grip to my new Redhawk .45 Colt/.45 ACP and it makes a substantial difference. I believe that the Tyler web site specifies this for Redhawk revolvers with standard factory grips, but it works just fine on the round butt.
This is my first experience with the T-grip. I like it, a lot. Looks good, also.