I went to see a neurologist from another medical group a couple days ago. He listened carefully, took copious notes, and, from things he said, he obviously had studied my file previously. After about 40 minutes or so, he asked if I had had a virus or been exposed to one back in Nov. 2009 when this numbness started. Although I couldn't remember, the doctor said this could be a post-viral rection--essentially my smaller nerves were damaged as a result of the virus. Although the nerves have likely healed, my body has retained a kind of nerve memory (like the body having muscle memory). I'm taking an anti-depressant now to deaden the memory in my nerves (lucky me, I'm hitting, like, every single one of the side-effects: nausea, increased heart rate). I've also been scheduled to get two more nerve tests to determine if this is, indeed, the problem.
The doctor said it may take several months of meds for results.
And, even if it's not, at least it was an answer.
Or at least it was something to try.