I have what I assume is a GP crossed with Golden / Chesapeake Bay Retriever or even Nova Scotia Duck Tolling Retriever. When I got him in Vermont about 6 years ago all they said was he is a "St. Bernard mixed breed" but really looks nothing like a St. B other than his coloring. He was from Quebec where GP is a very popular breed.
He is an amazing dog, but due to the fact he was found living on the street in Montreal, he has some issues around food and is also emotionally needy / separation anxiety but has gotten much better over the years. He learns fast, gets by on much less food than a GP weighing between 90-100 lbs. Also as he is almost 7 most people who meet him recognize he still acts like a puppy. Good with kids, other dogs, and livestock. But he does have a mind of his own and will wander if not fenced in or with people. I plan to get a GP or LGD and cross with a retriever as he gets older, it would help for him to have a companion and since he was neutered before I got him, sadly no chance of breeding him.