I was initially diagnosed with SFN.
But my symptoms are more like PN, and my Neuro has mentioned that.
My onset was fall of 07, and I'm still struggling with this without a positive diagnosis.
The only thing I'm on is gabbapentin for pain (which helps somewhat), Effexor (oddly enough I think better on it), and 500mg of Magnesium.
I went through all the testing as you have, and wanted to know each time "do I have this or that" hoping to get a final diagnosis.
My advice to you is make notes, lots of them. If you have a new symptom, write it down with the intensity, frequency, what you are doing at the time, etc. This can only help the Dr figure out what you have, and how to treat it.
I've had the numbness in certain parts, or all over. I have the washed out feeling every afternoon (and sometimes all day), the dizziness, the walking in a fog feeling, blurry vision, etc. The more you tell them the better IMHO. It's all got to fit somewhere.
Hang in there, you'll find out how to treat your symptoms, and how to live with this.