Is there any telling how big these puppies would grow? Is there some kind of formula for cross breeds? I'm not allowed to have absolutely massive dogs where I live by decree of the landlord.
Not sure what you mean with Napoleon bullmastiff? Are you thinking of Neapolitan mastiff? Unless the American Bulldog in this cross is of a very small type, then these puppies will grow big, and quick. You have no way of knowing how they will turn out, it's also quite regular that mixed breed puppies from the same litter turn out different from each other. Seeing as both breeds require serious breeders that know what they are doing to produce good dogs both mentally and physically, a mix of these is nothing I would consider buying or looking into. I would also wonder why someone has chosen to cross these two, and if they have done any health testing of the parents.
Agree with this. Neo's are HUGE, Bullmastiffs are pretty large as are American Bulldogs. All three dwarf your Staffy for size. I would run a mile for anyone producing this type of cross.
Nice looking dog there ! (Well apart from the ears!) Have you seen these advertised somewhere? Which site?