Everyone has forgotten about what is clearly the largest urban GOP enclave in the nation, at least if you are using "urban" to refer to building patterns rather than hewing strictly to center city boundaries:
The Cuban parts of Miami-Dade.
I mentioned that
, and after southern Brooklyn and Staten Island, that is certainly the most apparent, though with 2012 figures I'm not sure if a Romney CD can be drawn entirely within the urban parts of Miami-Dade (certainly can within the county). I do recall a member posting a McCain district in Bexar (San Antonio) though it likely included suburban areas.