If you are just looking for a Bullmastiff as a pet to love, consider going through a Bullmastiff Rescue Organization. Some breeders can take their dogs back or help you place them. Do not have to worry as to whom you get your Bullmastiff from. With the amount of money you are going to have to spend, you will need to interview several different breeders and compare between them to make sure you find the right breeder that fits your ideals, etc.
Puppies are always available, adults are available occasionally.
Less time to wait to adopt a Bullem Will depend on the breeder you choose as to when the next litter will come. If you are looking for a Bullmastiff to show or to breed, then a Bullmastiff Breeder is the most logical choice. But, if you are looking for a Bullmastiff to be a home companion, Bullmastiff Rescue would sure save you a lot of trouble and a lot of money. After all, a Bullmastiff is a Bullmastiff no matter where they came from. They all look the same, they all develop the same health problems, and they all have that Bullmastiff personality everyone loves so much.