Here's one I just finished.
It's a very much altered version of the old Stein Holster Company's "Snatch" holster.
The retention strap is not a thumb break, it's a pull-through, using a special heavy-duty snap.
To draw, you just grab the gun and "snatch it" out.
It was built to carry my S&W Model 66 with the 2 1/2" barrel and my limited production Model 66 with the 3" barrel.
The harness is 1 1/4" nylon webbing with plastic adjusters.
On the off side is a 2" nylon strap and snap assembly that snaps around the belt.
The off side assembly has swiveling loops for the 1 1/4" harness so the harness can move with you.
The connecter that's in the middle of your back is a version of the Galco harness assembly.
When properly adjusted the connecter lays between your shoulder blades, not in the middle of your neck.
The gun rides slightly farther forward then most horizontal shoulder holsters to give better accessibility.