Here's a jaw-droppingly awesome custom machine dating from 1951, with a completely hand-fabricated steel body (note the lack of seams) and components from 14 different vehicles. We're talking about a work of art right out of the golden age of postwar custom cars ... yet it failed to sell on eBay with a Buy It Now of $750,000. What is this thing really worth? Did the owner make a mistake by not selling it to an insta-millionaire during the dot-com boom? [eBay Motors]