I can very much relate to your post (except the Anti-Sulfatide Antibody). In my experience, they eventually cease testing, shrug their shoulders and your dx is Ideopathic Peripheral Neuropathy. They write the Gabapentin prescription and send you on your way. When you complain about the SE's, they substitute Lyrica of which the SE's are 10x worse and you beg to have the Gabapentin back. They comply.

Sorry for the bad news but there is no bright side to Neuropathy.