--and this is just my own, somewhat unscientific, somewhat biased, formed-by-collection-of-anecdotes-from-many-people-over-the-years-opinion, there seems to have been more success for many at finding a diagnosis at some of the neuropathy specialty centers--Cornell Weill/Columbia Presbyterian, Jack Miller Center, Johns Hopkins, Massachusetts General, Jacksonville Shands--than at Mayo for many.

Mayo is a wonderful place for reasons aformentioned, but I think some of the facilities above may have somewhat more expertise, reseach-wise and clinically. into neuropathies. Johns Hopkins is where skin biopsy was invented, Cornell-Weill has done a lot of work on autoimmunity and neuropathy (particularly as regards monoclonal proteins, neural antibodies, and celiac), Jack Miller does a lot of research into amyloidosis, etc.