Thank you for the reply and I am sorry for the delay in responding to you. I am traveling for work at the moment.
With the info you provided I have the following suggestions:
1. American Bulldog
The American Bulldog is a courageous guardian and a loving family pet, but it needs experienced handling and early socialization. Even though this breed is not as dog-aggressive as some bullies, it does like to play rough and won't back away from a confrontation. Unfortunately, some misguided owners foolishly put these dogs into fighting arenas with Pit Bulls and other breeds, almost always with terrible consequences.
2. Alapaha Blue blood Bulldog
An excellent guardian, the Alapaha Blue Blood Bulldog is also a devoted companion. Used as a cattle herder, as well as a boar hunting dog in the past, today's Otto is bred solely for protection duties and family life. This is a muscular dog, with a broad head, relatively short muzzle, wide chest and strong bones. The ears are left unaltered and the tail is never docked.
3. and Finally - Cane Corso
If bred properly, the Italian Cane Corso Mastiff is of sound temperament, easily trained and a breed which makes an excellent family dog. Very affectionate towards children, it will gladly give up its life to protect them. This breed is completely devoted to only one master and very loving of its human family, but is naturally aloof with strangers. Although not as dominant as the American variant, the Cane Corso Italiano is still fairly dog-aggressive and at times overly protective, so it needs experienced and responsible handling. This is a very athletic and fast dog, possessing great agility and stamina, requiring a reasonable amount of exercise and more importantly, it needs a job. The body is muscular, with a straight back and long sturdy legs. This powerful Molosser has a deep and wide chest, with a strong neck and an elegant broad head and muzzle. The tail is docked and the ears are usually cropped, but unaltered specimens can be found as well.
Those are the three breeds I would recommend in order of their listing. The top two are probably easier to find in the USA and you may have to look very closely at the breeders of the Cane (pronounced Cahni) Corso. Note it is not pronounced as Cane since Cane' is the word for dog in Italian.
I would be interested in whatever decision you make regarding your next dog and please let me know if I have helped you.