This is Funny, my dog is now 6 but we got him as a puppy, his name is Buddy ... he is 1/2 Golden Retriever, his other 1/2 is Bernese Mountain dog though. We thought he would weigh about 90 lbs too (mother was Bernese and weighed about 90, father was a retriever, they come in about 70). The dog grew to 140lbs!!! Best dog ever though, very lovable, great around kids, ect. Clues in on every noise though and doesn't like strangers. He has a bark and a growl that will scare anything. I came home late one night and he was in the garage, he's almost all black and is invisible at night. I came across the front yard and neared the driveway. This loud menacing growl came out of the garage and sent an instant chill up my spine. I called out his name and said 'Buddy, it's just me'. Then this huge happy friendly dog came running out of the garage with his tail wagging when he heard my voice. If I'd have been a stranger, I think I would have dropped on the spot. He has a deafening bark too, drives you nuts sometimes because he can have a lot to say but no sound outside escapes him. Shepard and retriever should be a good mix too. Both are smart dogs, both make good pets (hard to beat retrievers for friendliness), both have very keen senses, and it will be a large dog with a good bark. And yea, I'd bet about 80 lbs. Should make for the perfect dog.