My dog also has seperation anxiety, though I'll admit its a very mild case.
I found that having a routine in the morning helped on week days. That way, he'd know I was going to work and when I would be home. Every morning I did exactly the same thing in exactly the same order. Before leaving I would put him in his pen, give him his carrots, turn on the radio and give his safety cue of Cheerio.
This did two things, it made him much less anxious when I went to work, which was great, but it didn't help if I left any other time.
I also found that he was less anxious if he could sleep in my room and basically be around me at all time when I was home.
I'm sorry if that's not much help, but you've done all the reading, so you know what all your opitions are, and the cause for the anxiety so you'll be able to find something that works for your dog. You might have to hink outside the box and re-organize you life a bit, but you'll find something that works... Eventually