One of the things they wanted to do with the Chevy, was bring out all the famous people who hawked Chevy in the past... Have them all seated in a number of old model Chevys that would float past through space. Well, they got Dinah Shore... The kicker was, they wanted Dan Blocker, who did a lot of spots in the 60's. Well, Dan, had been dead for over ten years...
A likeness was found at the Hollywood Wax museum... Weeks of negotiation and planning went on to try and overcome the problem of how to bend a wax sculpture to get it to fit in a car... They couldn't, so they figured they could drill out the bottom of the car and let him stand... Then, they could rotoscope out the legs coming from the bottom of the car...
Then, the deal was finally killed when the wax museum people came in to see the filming process. The lights were so bright and hot, they feared their wax sculpture would be ruined and refused to rent it.
Just great... Of course, that was all in the documentary (or on the cutting room floor of the documentary).