Not sure if you are interested in a DA revolver, but Ruger still makes a single action convertible model.
I have a Ruger Vaquero with a bird's head grip chambered in 45 ACP. It's single action only, but I really like it. The cylinder is machined so that no moon clips are required. I don't see the bird's head model at Ruger's site anymore. I believe it was a limited run, or "distributor special", but they still show another with the standard cowboy grips.