1884 De Dion Bouton et Trepardoux Dos-a-Dos Steam Runabout The 1884 De Dion Bouton et Trepardoux Dos-a-Dos Steam Runabout sold by RM Auctions for $4,620,00 in Hershey. © RM Auctions Home » International » 2011 – Ten Most-Expensive Vintage & Classic Cars Sold at Auction » 1884 De Dion Bouton et Trepardoux Dos-a-Dos Steam Runabout