Here's the GM Futurliner we saw on the way out. GM made 12 of these for the "Parade of Progress" that drove around the country in the 1940&41 and 1950-53. These trucks opened up to display all sorts of future tech, like microwaves ovens, stereo sound, television.
There are only 6 or 8 of these trucks left -- the owner of this one has another that is currently undergoing restoration.