Shell,
You're right about border collies. My elderly parents have one that takes care of them. He watches over them and takes Dad for walks. He's never had an accident in the house. They are so smart they anticipate needs before they happen.
Also on the list should be Australian Shepherds. We had one that would bring us his empty food dish when the kids didn't feed him. He would go to the car door and try to open the door with his mouth when he wanted to go for a ride. He was smart in so many ways. And very protected.
Did not bark much.