Sounds like you've tried everything - and I wonder if you've tried too many things and he's just confused and has not enough structure.
Forget the pacifier - kids can't figure it out at all. You cannot sleep with him his whole life, but if you try co-sleeping, commit to it.
Reading and singing? Too much stimulation. He's too dependent on you.
Is the reflux all taken care of? If that's ruled out, then it's just habit and being calm.
Cry It Out - not sure how you did it. If you did it cold turkey, that doesn't work. I agree with Doris Day - read up on Ferber which is not Cry It Out, it's sleep training. Do not give up on it. Commit to it, be consistent with both you and your husband doing exactly the same thing, and saying the same words. No caving in or quitting. For us, it took 3 days. Even if it takes a week, it works. Get some help if you need to, either Grandma or a night aide or sending the other kids (depending on the age) to a neighbor or Aunt Millie.
He needs a full night of sleep for brain development, so that's your goal. It has as much to do with him as it does with the rest of you being exhausted. This is a gift you are giving him, not torture. Just as you teach your kids on an ongoing basis not to jump around while they are eating or cross the street without holding hands, and you reinforce it each time, you have to do that with sleep.