That's great! Deterred by barking and growling? A 65 lb Dutchie or Malinois, yes. I love Aussies and I've known a lot of them, but I've yet to meet one that had the stuff to take down and hold a 200+ lb man.
I'm sure some do, my GSDs either recognize them as a threat or can be trained to, but...
I agree a well bred Australian Shepherd could potentially preform both duties for you. Although a dog that size would be of limited usefulness against a human, if push came to shove.
As mentioned above any dog with the necessary prey drive to protect is going to need training to be good around...