There were 6 made for the films, 1 caught on fire, 2 rotted into the ground, the film studio still has 2 and the last one is in a private collection somewhere.... could be that one?!
however.......... there is one for sale on fleabay usa for $450,000!!! I think this one is a bit special tho, took him 8 years to build and for that price it better take me back to the future!
http://cgi.ebay.com/ebaymotors/BTTF-...item2eb430d157