Hi Ann, I have only one Bullmastiff for the moment, my latest male went to the rainbow bridge may last year. I totally love the breed, but there are blood lines with individuals who can be a bit on the "sharp" side, a little over protective. My boy who passed away last year was one of them, he was the most darling dog in the family, but he was way too over protective, I have done obedience competition with German Shephards before, so I figured I was pretty well equipped to deal with it, but it was a struggel.We loved him more than anything, but he was the kind of dog you always always had to watch with other people, the slightest move he thought was a threat to us, he was ready to protect.
Having said that, I think a Bullmastiff is a wonderful breed, the female we have now is not at all as protective, she is easy going and very very lovable, loves everyone and everything. The advice I would give you is to research very much, visit AKC's website and click on "dogowners to be" or whatever it says, there you go to "breed referal" find Bullmastiff and contact the person who is the breed referal contact. They should be able to give you a list of breeders, who follow all the ethical rules and regulations and keep up with all the health cert's. I would first see about the breeders fairly close to you, so you can go visit, see if it is how you want a breeder to be, how they have their dogs, how many litters a year, do they keep any of the offsprings. Are they working them, showing them. Ask all the questions you can come up with, write them down, so you dont forget anything. Meet as many dogs as you can from the breeder and the bloodlines they are using, ask for referenses. Once you have your puppy, make very sure you take it out as much as possible, meet people, new places and odd things.
If you have any more questions, I will be more than happy to try and answer them. either here on the board or in personal messages or email me.
I hope this was a little help, and dont let all this scare you off, they are wonderful dogs and I wouldnt want to be without them, so I am glad you are planning ahead and have plenty of time to find the very right breeder.
Marit