What about the Newfoundland? When we lived in Canda some people we knew had one. It could stand up on its back legs and put its front paws on my 6'4" stepfather's shoulders and its body was only at a 45 degree angle. And it was built like a St Bernard, all barrell-chested and hairy, must've weighed 200 - 250 lbs. Not as tall as a Great Dane, maybe, but definitely a huge animal!