About six months ago I resolved to try an OWB holster for a J-frame for the first time ever. Accordingly, I looked around carefully and decided on a "Micro" from UBG Holsters.
I am pleased as punch to be able to say that I got it right the first time around. There may be other OWB holsters that are as concealable, but I can't imagine any more concealable than the Micro. It has the three features that you need in order to hide a handgun successfully OWB:
1) High ride - It is true that the short-barreled revolver lends itself to OWB concealement because it's short by its very nature, but the Micro does everything it can to boost it even higher, so that there is very little of the muzzle left below the belt - maybe 1" or so with a S&W Airweight.
2) Lots of cant - You can specify how agressively angled you want the gun to be when it's sitting in the holster. I told Mr. Gable of UBG that I wanted the end of the gun's grip directly over the muzzle. He followed my instructions faithfully, and consequently this thing is a joy to wear; so glad I insisted on 30 degrees or so of cant. It's not so severe as to make drawing the gun awkward, but it does let you wear the holster at the 4:00 position and still hardly print at all when you bend forward in a chair or to pick something up.
3) Rides tight and close to the body - When it first came, it was stiff as a board and was really annoying to wear. But after two weeks of use, it had perfectly conformed to my body and hugged me so closely I was (still am) amazed. Note that neither the belt slots nor the holster body is pre-formed in any way. You break it in and make it adapt to your individual body shape, which it will, given a little time. It's well worth it.