I have a Kramer Scabbard OWB holster in horse hide for my Sig Scorpion. Kramer will make holsters for the Sig profile with the rail and the holster works very well. They are not cheap, but not many custom holsters are. I think I paid $126 for this holster about a year and a half ago, but am quite happy with it.
I see Kwood has already been here, but I can vouch he does good work. I have a Colt Rail Gun I wanted a holster for and he was able to make a very nice one.