As for moving as fast as GSD in AKC conformation. The SV style shows I have attended (which was two, for full disclosure) had the dogs not only trotting as fast as their handlers could keep up with them, but they were also doing it for 20+ minutes at a time, and for a dog that moved on to another ring, those dogs were expencted to trot at that pace for much longer. Not only was it a test of conformation, keeping their gaits smooth during this trial, and keeping toplines and showing stamina, but the dogs showed obedience and character in this task.
I was marveling at the handlers because they were running fast to keep up with these dogs pulling at the end of their leashes. No way could I run like that for 20+ minutes, go to another ring and do it again, and possibly several more times. Then to top it off have an obedience trial after.
I would love to see an American bred, AKC style GSD working as a true working dog, and this isn't just a jab at that variety. I honesly would love to see more utility and work ethic in the U.S. bred dogs. However I have not heard of one doing herding as a functional job, working with police doing scent work or patrol, being a service dog, ect. There may be Am-bred GSD with some work ethic or insticnt but for them to actually do the job, like I said, as a functioning working animal I have not heard of that for a very very long time. Not only are the minds of the dogs not very suited for this, but their bodies aren't either. JMO, with experience in the breed talking here though.