Necessity is the Mother of Invention... I remember reading an old Popular Mechanic's magazine, where someone had converted a gas engine car over to a steam powered arrangement. I wish I had access to that old article, because it was really interesting how it was done, and it performed well too, if I remember right. It was an "Ugly Beast" though, and the Yugo conversion was what brought it to mind.
"Remember the Alamo"!