What a difficult situation. All I can suggest is that you check out - if you haven't already - fibromyalgia (FM). FM is an often misdiagnosed disease that causes widespread body pain. It appears to be caused by a sensitization of the pain producing processes in the central nervous system. I would think that some of the doctors surely considered this diagnosis but perhaps not. Since the cause seems to be in the brain its treated differently than other pain disorders.
Theres an excellent fibromyalgia section on Health Central
http://www.healthcentral.com/chronic-pain/fibromyalgia.html
Since you've really struck thus far you might try alternate methods of turning down the pain response such as meditation, guided imagery, etc. They can be surprisingly helpful in alleviating pain. Poor sleep has also been shown to quite quickly lead to widespread body pain. Be sure that you're able to get good sleep every night.
http://backandneck.about.com/od/alternativemedicine/Alternative_Medicine_for_Back_and_Neck_Injury_and_Chronic_Pain.htm
http://www.ahealthyme.com/topic/painseries2
Good luck!