Don’t give up. There is always a little bit more that can be checked, a fresh set of eyes could make the difference. Have you had an expert work up by a rheumatologist/immunologist? Have the basic autoimmune markers like ANA been checked and inflammation or lack of it noted? I can’t pretend that I would catch anything that all of these experts have missed. I’ve heard of strange syndromes following an infection like: http://www.ninds.nih.gov/disorders/gbs/detail_gbs.htm
but there are less obscure things that can cause strange overlapping symptoms, like Lyme Disease.
If you haven’t seen an rheumatologist/immunologist put that next on your list. If you have, you might want him/her to check for more antibodies. I was very sick for several years and kept going to the doctor and complaining about it. They ran lots of blood work and found nothing other than mild anemia and that I carried HLA-B27. I started having episodes of freezing, shaking and weakness lasting several hours. Eventually I collapsed in the waiting room and when I was admitted into the hospital they ran some tests and told me that I had Grave’s disease and was experiencing thyroid storm. Not a parallel with you but the point is that I bugged them for several years and it turns out they never ran thyroid tests until I almost dropped dead. Even good doctors can have a blind spot so you have to be a squeaky wheel, unpleasant s it may be. Hang in there.