I thought Kelpie mix too. Not sure if they're common in the US though. Could very well be Border Collie mix and they may just get their colour from BC too. But yeah, I thought Kelpie mix the second I saw them.
However like everyone has said...it's extremely difficult to tell when they're pups. You'll have to wait until they're much older, maybe 6mths?
I think they'll be medium sized dogs.
Cass.