B.G.
I have b/b twins that are 10 now, and they did not sleep all night until they were 2. On my next baby I let him cry himself to sleep. It seemed harsh to me at first but you have to do it to survive. I finally put a full size box spring and mattress on the floor ( so if they fell off it would not be a big deal) and put them back together. The first few nights I had to be consistent and put them back in the bed every time they got up, but it got easier and they started to sleep all night very soon. They needed each other. You need to do whatever it takes because after so long of no "good sleep" then you are not a good mom anymore, believe me I know!!
I hope this helps. It looks like you have lots of good thins to try!