SEVERE Doggie separation anxiety, NEED HELP!!!!?

I rescued Bear on March 26, 2010. He had been in the shelter for 6 weeks. I don't know much about his history, but, can guess he was abused and neglected. I believe he was just left to fend for himself outside. He was infested with ticks. For the first month I had him, he REFUSED to go outside, I'd get his leash on him and he would immediately panic. I would pick him up and take him out and he would simply sit down and shake uncontrollably. It got to the point where I felt like I was doing more harm than good, so, he began using puppy pads. I was eventually able to gain his trust and convince him that going outside was okay. Now, he loves going out and going for walks. Shortly after accomplishing the huge goal of getting him outside, he began with the extremely destructive behavior. The issue I'm having now is that he has SEVERE SEVERE separation anxiety. He has eaten all of my window sills down the the drywall, eaten drywall, stripped door, window and wall trim off, he has destroyed all my blinds, eaten my couch, pulled the mattress off the bed in an attempt to get at the upstairs window. He destroyed his first crate, by eating the plastic side and opening the wire gate enough to slide through (I still don't know HOW he got through the spot he did). I got him an ASPCA metal cage, which I reinforced and double locked the latches. He bent the wires and managed to escape through a 3 inch gap. He's 50 pounds and a medium sized dog... Last weekend, my vet put him on Reconcile. We have been doing the behavior modification training, I have desensitized him to my keys and the door locking as I leave. The day before yesterday, I came home from work and there was very little damage, I felt like "Yay! Finally, SOMETHING'S working" Yesterday, I came home and he had taken the cover off my a/c unit (I live in an apt that has an a/c unit like hotel rooms have) and he had stripped more trim from around the door. I tried bitter spray, it had absolutely no affect on him. He continued to eat the walls and woodwork. Funny thing is, interestingly enough, from the time I adopted him, whenever I'd come home, he was neither anxious, excited or really very concerned that I was home. It seems like his trigger is me leaving on work days. I have been changing up my routine, my habits in the morning on work days, as well as on weekends. I don't say good bye to him in the mornings or make a big fuss about my departure. I have tried attention diverting toys, bones, etc. However, he has absolutely no interest in toys. He has an entire basket of toys that he has never even attempted to touch. He has very little interest in bones. He is not treat or toy driven. He gets walked 3-4 times a day for 30-45 minutes at a time. I'm running out of options to help him out. I can only imagine how frustrated he must be, because I know how frustrated I am.