Thanks for the input, guys!
At the vet he is listed as a terrier mix, so thats what I usually tell people who stop and ask about him.

I know the family who rescued him has mentioned that they think his mum might have some Pointer in her. It makes sense and might explain some of his coloration (ticking seems pretty prevalent in most Pointers). He sure doesn't have the matching personality, though.

When he was a pup he often got mistaken for a Pit mix. And I have seen plenty of Boxers, Pits, and Am Bulldogs with similar coloring. I try to keep in mind that his mum and 6 pups were found in the middle of nowhere in a field, so more "country" dogs might be more likely than others. Pits are extremely popular around these parts, though.

I am sometimes so tempted to do one of those silly DNA tests that supposedly reveal the breeds your dog is mixed with. I know they aren't really accurate, but I am just curious what it would say. Probably something ridiculous like Pug and Poodle. lol