Tablas Creek Vineyard has some vegan options

Company email (April 2012): "We do employ the use of fining agents in some of our white wines. In some years, for select whites, we use bentonite for protein stability (so the wine does not become cloudy if left in a hot car) and/or Potassium Bitartrate (Cream of Tartar, which is basically a fine powder form of tartaric acid) for cold stability, but both of those are vegan products. We use casein on our Marsanne at harvest, which means that our varietal Marsanne and our Cotes de Tablas Blanc (which contains Marsanne) are the only two wines we produce that are NOT vegan."