As far as shipping dogs - I have had three dogs shipped to me so far. Of the three, one had a very tough time with it. She hadn't been properly socialized as a young puppy, was nearly five months old and had never even been in a kennel. She needed a home, I offered one, and she got stuck in a kennel and shipped from Ohio to Alaska. It's taken me years to get her through all her lack of socialization and the trauma of being shipped like that.
But the other two were from reputable breeders who handled the pups well beforehand. Both puppies were crate trained young, had some socialization and had ridden in the kennels for car rides frequently. Both were shipped at just over 8 weeks of age. Both showed up as happy and confident as I could have wanted.
You'll be looking at a bit of expense with shipping - not only the freight cost, but the health certificate too.
As far as the ACD temperament, unfortunately around here there have been some really nasty ones. At the vet clinic we had a few clients with ACD's and some of them had to be muzzled for everything. And I had one particularly memorable dog come through my class who had no socialization as a young dog, had been allowed to get away with everything, and then when it started being dominant aggressive as an adult they decided to come to class. The dog bit me several times.
But I've met some really nice ones too. I think it's probably much like the chows or shepherds - if you start out with a good breeder who breeds for temperament as much as everything else and who handles the puppies well during those first 8 weeks, and then you continue the socialization and training, you'll end up with a nice dog with a good attitude.
Melanie and the gang in Alaska