A quick follow up on this... these are the only two beers I can think of that include grapes (in the form of must):
The Bruery's Vitis Series, http://www.thebruery.com/beers/specialcollection.html
The Bruery does not provide a ton of information on the grapes, but it looks like they add them to a year-old sour blonde ale and let it ferment out in stainless steel. It is then transferred to oak and aged for 10 months.
Stone's 10.10.10 Vertical Epic Ale, http://www.stonebrew.com/epic/w101010recipe.htm
Stone added the must when the beer fermented down to 10 Plato, so as to limit the yeast's exposure to simple sugars. The must made up 10% of their volume.