Three space colony summer studies were conducted at NASA Ames in the 1970s. A number of artistic renderings of the concepts were made. These have been scanned and are available here as small, medium, large, and publication quality jpeg images. Scans by David Brandt-Erichsen.
Images are not copyrighted. Please credit photos to NASA Ames Research Center.
I remember seeing pictures like this when I was a kid, and thinking that this would happen in my lifetime.