WOW - I feel for you!!!
I've had two dogs with separation anxiety ... an uncle and his nephew. To be honest I lucked out resolving the issues and I can't say they would work for any other dog. Both boys had lots of exercise, I seldom left them alone for more than an hour or two, plenty of toys were available, etc. I know some of their relatives also had this problem so I honestly believe it can be heriditary????
With Niki, he not only learned to unlock the windows, open them and escape from the house (fortunately he just waited by the gate for me), but nothing could hold him (wire crates and plastic ones). Out of desperation I purchased a 700P Vari-Kennel which kept him happy and contained ... and yes, I know he could have destroyed it had he wanted to - I could never figure out what he liked about this type/size that he didn't like about other crates.
With Mac he destroyed all crates including his Uncle Niki's (but fortunately he stayed in the house). But he was happy having complete freedom of the house so that's what I do ... Slider, Bruiser and Faith share the dog's room, Mac has the rest of the house.
In other words, I didn't really resolve the problems, I just placated the dog by finding out what he wanted! Not a good solution, but it worked.
If I had not found a resolution to this nasty problem, I would have purchased a dog jail. Well, actually I did get one for Niki ... it was built by a friend up in Canada who dropped it off at a mutual friend's house in VA. I let my friend have it since getting it down to FL would have been a big problem (it weighed about 400 lbs). I later found they make some commercially that are much lighter in weight.
Here is an example of a crate I would have looked at - I'm not saying I would buy from this company, but it has examples of what appear to be crates that would be difficult or impossible for an escape artist to destroy.
Dog Crates & Accessories, Aluminum Dog Crate, Powder Coated Dog Crates