I can't recommend any breeders, but I know if you will share any details on your plans for the gsd, others on here will be able to help out better. Plans such as IPO, SAR, etc. or if you're just looking for a level headed dog that will just be a loving family member. The more they know about what you want, the more specific they can be with breeders.
Finding a good breeder starts with what kind of dog you're looking for, not with what color you're looking for If you start with thinking about what you want to do with the dog (sport, etc), what kind of energy level, temperament, etc, you'll have a much better chance of getting a dog that suits your personality... and THEN you look for a sable. Where are you located?
A buddy of mine I work with recomended his breeder, his dog is amazing. Loyal, level headed, always listening, very very careful with what he does and the dogs only a year old.
The breeder is really a kennel owner with a family dog that they have for breeding. Shes very conservative with the litters and makes sure that the "buyer" is getting the right dog. All of her dogs wind up to be black or sable.
Good blood lines ( i dont have specifics yet) and very good temperament making them a good companion.
Im just looking for a dog thats willing to be aware of whats going on around the house when im not home for my girlfriend and be a warm dog with the, people we know. He claims all of her dogs meet that.