i met this woman in LA last week who trains them....check out her site
www.turnaroundtraining.com
when a pit bull has bitten another dog or a child or something she gets the dogs and re-trains them. People pay her to get the dog to an acceptable social level again. If you look at her site it answers a lot of your questions and concerns. I had a lot of the same fears and believed the rumors about pits "turning" on their owners. You should call her and talk to her !! If her contact info isnt on the site, let me know I have her phone number.
GOOD LUCK