I finally found this in PDF form!!! Although it's the source for Oneil's _High Frontiers_, I've always found the source material far more interesting. Again, horribly dated, but I don't know of any publication better for lubricating the imagination.
"Space Settlements: A Design Study (1977)" - http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19770014162_1977014162.pdf
The NASA link is dead so I'm linking the copy I posted on Scribd that can be read online or downloaded from there.