But--I wonder if those symptoms are at least partly central nervous system, rather than peripheral nervous system, based.

The problem with neurological disorders, and much of the reason the investigation into their etiologies are so long and expensive, is that problems with the CNS can produce symptoms that can exactly mimic, in intensity and distribution, problems in the PNS.

Many now think that migraine is actually a form of seizure disorder. And many seizure categories can produce parasthesas--odd sensations--in areas other than the head by permanently changing the nerve firing patterns in the areas of the brain that correspond to the sensory area singals from that part of the body are processed within. (Interestingly, many of the same meds prescribed for peripheral neuropathy symptoms were originally anti-seizure meds.)

Have you had a full EEG done since this all started?