I think people are getting away from the P4P thing. Yes, a Caucasian Shepherd or a large kangal can kill a pit-bull more often than not, but they're literally 3 times the size of a pit bull. It's like comparing a 100lb man to Brock Lesnar.
The fact that game pits of the highest fighting stock actually kill these large dogs sometimes really says a lot about the breed.
As far as the small dogs go, someone was mentioning the jagdterrier. I think this might be the answer. While a game JRT and a jagdterrier are pretty much the same dog with the jagdterrier being slightly bigger and the JRT probably being slightly more athletic, the jagdterrier breed hasn't been watered down like the JRT has. Most jagdterriers come directly from hunting stock, and are specifically purchased as working dogs, while most JRT's are pets that simply still have a very strong prey drive.
Average jagdterrier > Average JRT
I don't know much about the patterdale terrier, so I can't really form an opinion on them. I've never actually seen one.
http://dogs.bsl-sbt.com/imagefiles/dogsimages/patterdaleterrier_largegame.jpg
Patterdale terrier
http://www.texasjagdterriers.com/Lexy_on_possum_002.jpg
Jagdterrier
http://i99.photobucket.com/albums/l292/cooch01/rathmoy018.jpg
JRT