Another update from the OP
Hi all, thanks for lots of good advice.
The appraiser came back out, took the measurements, and is revising his appraisal to reflect square footage somewhere in the 1800's. He said with the comps he is finding that the new value is going to be $280,000. While this is not as high as I hoped, it puts our current LTV at 78.57%.
Now comes the fun part of figuring out how I can actually get this corrected. The appraiser said I should contact my lender and tell them he made a material error in the appraisal and it is being changed. I contacted the lender and they said I need to contact the servicer or the loan (Wells Fargo). I called Wells Fargo today and a not very helpful woman told me that Wells Fargo's policy is not to remove PMI until the LTV reaches 75%. That seems wrong to me as I understood the standard to be 78%. In addition, my closing documents show in the PMI disclosure that our PMI is scheduled to terminate when our LTV goes below 78%, and that we are entitled to request cancelation when it goes below 80% (which is now if you use the correct valuation).
I know this stuff is really out of the scope of an appraiser, but I figured some of you might want to know what's going on with this situation.
As far as reporting the appraiser in question, at this point I am putting all of my energies into trying to get my loan fixed. I'll decide later whether reporting him is the right thing to do, and whether I have enough energy to actually put forth that effort.
Thanks again for all of your help! If this ever gets corrected I will post a follow up to let you all know.