Check this resource, it has all you need: The Library of Congress, especially the H.A.E.R. collection, I can browse that for hours!
http://www.loc.gov/pictures/collection/hh/Would you care to do Thurmond, W.Va. for instance?
You can find detailed drawing like these and many more, ready to model:

Or historic Cleveland, Pittsburgh or any other major US city that has a university with a history department and electronic library.
Pay special attention to the rapidly vanishing public and civic architecture from the 20's till 40's in Art Deco style.