As long as it's not a Gordon Setter. Mine is almost 4 years old and still bouncing off the walls. And she's all showlines. Had a field Gordon before and he didn't start settling down until he was 8!
True, I haven't met any calm Gordons that I can think of. But several really laid back Irish and English. English especially.
Vin, are they wanting a puppy or young dog, or would they consider an older dog? A middle aged dog of most any breed could fit the bill, including GSDs. Though there are some serious couch potato GSDs and breeders of that type that produce the perfect dog for them in a GSD looking package if they are dead set on a GSD.