Jack:
I think you're in luck, but you'll just have to switch gears and start looking for "Blackhawk" grips, as it shares the same grip frame as the Old Army.
I have a set of Pachmyer rubber grips for mine, and I use them once in awhile, and they are "fuller" than the originals. But my "best grips" is a set of striking silver/black laminate grips made by the old Lett Company (out of business now, was once a custom maker for Ruger), and they contrast well against the stainless finish on mine.
But here again, you're in luck, because with the growth in Cowboy Action Shooting, there are many custom grip makers out there today making grips for the Blackhawk. Some makers will make "fat" or "thin" grips too. In addition, you can check for BH grips made by Eagle, Hogue or Herrett too.
Good luck!
Old No7