I've seen a pit bull/St. Bernard mix, the father was the pit bull for the one I saw and the mother was the St. Bernard. The puppy was shaped liked a St. Bernard but had short hair and was brindle like a Pit bull and as it grew generally looked like the biggest Pit Bull you ever saw, because of the jowls, but even when I last saw it at six months of age(when it weighed 76 lbs already and wasn't done growing) it was sloppy and friendly like a St. Bernard,just looked scary as h---.