So I sat down and started "courting" this dog. After about 15 minutes he calmed down enough to come near me but when I stood up he started barking and lunging again. It took me another 15-30 minutes before I could even hold his leash. He started walking around calmly when I got hold of his leash so I thought the worse was over. When he realized that I was holding his leash and he started barking and lunging again. At least he ended this behavior quickly - I don't think I would have had the energy to hold on to him and prevent him from biting me for more than 5 minutes.
When I started training him I realized that there were a lot of things he was afraid of, to the point he could not even look directly at me out of fear. I started training him at the same time trying to find out what makes him happy. I tried treats, toys, his own food and I finally realized he loves to be rubbed.
After almost a week with him he treats me differently now. He jumps around when he sees me and tells me what he wants to do before training starts. He looks directly at me, he chooses his treats, he complains when I rub him too hard (he likes the gentle touch), he gets really excited about hanging out with my dogs, he tells me exactly where he wants to go but takes into consideration when I give him commands. He is willing to make friends with people, especially when we are walking around. We still have a long way to go but it really is fun being able to play chase and hide and seek with him now. He even cries when Charis and Keegan go for a walk without him.
He turned out to be a real gentle and sweet dog who just needed the gentle touch in order to see me and the world differently.