I really feel for your situation.
As others have said, unfortunately, Bark Busters is not a great source of behavioural advice - however that is absolutely not your fault - the fact that you sought help shows that you have tried hard to help your dog. If you feel you want to keep trying, I would urge you to find a qualified behaviourist to help (I'm guessing some of the PMs you have will have given you some recommendations).
If you do decide to rehome, please don't feel you have failed him - ensure you use a rescue who will provide behavioural support to a new owner and know that you are giving him the chance of a life where he can improve. I live with a highly strung dog, who could easily have escalated to aggression, and managing her alongside my toddler is very hard work, so I can only imagine the hard work you are putting in every day keeping your family safe while also meeting the needs of your dog. No-one can doubt your devotion to him.