I somewhat achieved this using an existing city on Kolgujev and then adding buildings to it in my mission "The City of the Dead"..
I think the best way to do urban warfare in OFP is to create a custom Island for it though.. Using buildings placed in the editor is fine for a human player, but the AI has no idea what to do most of the time.
However, on a custom Island those AI problems would be lessened, cause the city is supposed to be there. (if it's done correctly, of course)
And, IMO there are no suitable cities in Resistance for Urban Warfare, unless you add on to them. (The cities are not large enough or "closed in" enough, IMO)
Asmo