Not a German Shepherd, but I love Red Dog.
The dedication portrayed in that movie is outstanding.
The dog portrayed in I am Legend was amazing and shockingly, my mum had a German Shepherd like that when she was a teenager. That must have been 30+ years ago??
EDIT: After that first dog my mum got three other German Shepherds but none of them were like her Igar, he truly was the ideal German Shepherd dog if the stories were true, but a dog of a life time apparently.