Galco makes a model just like that. I think a J hook attachment is worse than useless though. High Noon holsters makes an identical holster with an C hook attachment that doesn't rely on your pants waist band and to hold the weight of the firearm, but attaches directly to the belt as it should. This could be from any number of manufacturers though as this is a common design.
I agree with Matthew03 on this. If you want a leather IWB type holster, I think the Milt Sparks Summer Special is the prize winner.
You can go on forever discussing IWB holsters, but check out crossbreed holsters and milt sparks. If one of those two doesn't work for you then there's no hope.