Not much is known about Disney Imagineer Clem Hall, but he was responsible for one of the earliest concept paintings of Space Mountain for Walt Disney World. With the Grand Prix Raceway to the left, and the Skyway building to the right, Tomorrowland was planned to hold many exciting attractions above ground, on it, and in outer space! As you can tell, the completed version of the Magic Kingdom's first roller coaster attraction shares only a bit of the look shown above. I've got a few more of these around...somewhere.
(Art copyright The Walt Disney Company.)