Been awhile since I owned one, but as I remember they are fairly easy to make yourself if you are so inclined. Find the woold you like, and just trace the originals.
Roy Fishpaw makes custom grips but they are a bit pricey and will take time waiting in the queue but the work is outstanding. He has no website. Finally, there is an OEM supplier (I forget the name) that is in the Midwest that has made wood grips for S&W and Ruger (on the special models that had Rosewood grips and gold triggers and hammers made for a distributor).
These folks make grips for Ruger and the quality is excellent. They used to make full wood grips like these on my GP100 but I don't see them in their catalog anymore. They were more square butt and I rounded them off but you get the idea. You might ask if they still offer them. http://www.lettgrips.com