Chris I don't see how you could breed a staffy with anything to pass it off as an American Bulldog pup. I was at the vets with my staffy who was 3y.o at the time when a farmer brought in a AKC registered bulldog pup at around 12 weeks old for jabs, this pup was almost as big as my staffy. He had an adult in his Land Rover and he was huge, much larger than any Rottweiler I've ever seen.
If that DDA list gets ammended, it'll be very draconian and anything 'interesting' will be on that list.
Like garethR, I too doubt the source of that list, that's tthe work of somebody with an axe to grind and there are no toy breeds on that list either.