Tamaskans breed true and are accepted in ARBA. There is no GSD in their blood.
Totana-Piper Hll is an American show kennel. No experience with them, though. And there are more places to look for a dog than schutzhund clubs. Hit up a few dog shows, do some more googling, email some breeders and talk to them.
Jackie and the Marcato Shepherds
(and one cat)
Strauss: Service dog/old man
Wesson: The soon to be champion
Loch: Service dog in training
Barrett: The Frikken Tikken