Your dog looks like a lot of APBTs from weight pull lines that are known to be mixed with bullmastiff, bordeaux and american bulldog or some like many bandogs out there. Also resemblance a Pit/Shar Pei/Mastiff type mix. I'd say any of those breeds Shar Pei, Bullmastiff, Bordeaux, American Bulldog or other mastiff type breeds. He is super cute.
He looks exactly like a Dagger female I know. Not too far off from some of the Camelot dogs either. Hmmm really tells you something.
If you watch this video and view the link, they have a dog called Peewee I think is similar to your dogs in looks a bit.
http://youtube.com/watch?v=5naAgPI_qSw
Check around with some bandog people, you will see lots dogs that look like these 3 also.