As someone who has seen so many toys of questionable temperament (yes EVEN after winning their breed in all-breed shows), PLEASE grill the breeder on how s/he evaluates temperament and how she emphasizes temperament in her breeding program.
Regarding GSDs for show, there are two main line splits: German showline and American showline. German showlines would get laughed out of most AKC rings and American showlines would get laughed out of most SV rings. There is a ginormous debate on whether either line is good for the overall GSD breed. It's also an extremely political breed to show and unless you have a pro handler, you would be better off in UKC shows. In fact, many people will agree that it doesn't matter what kind of German shepherd you get for the AKC ring, so long as Jimmy Moses is on the other end of its lead you'll win them all.
If you are interested in American lines, I would contact Daphne of Andaka-Zederland Kennels. I don't have her current contact info but she is over on the germanshepherds.com forum as username "Andaka." Her dogs are titled on both ends and she always has good recommendations for other kennels who value temperament as much as conformation, if not more.