The wordpress codex says that a category and subcategory cannot have the same name, even if the subcategory has a different parent.
I'm going to run into this exact situation and am trying to think of a solution. My categories will be US States > Military Bases > Neighborhoods. The problem is that neighborhoods from different bases may have the same name. Like a subdivision called "Stonebridge" near Shaw AFB and Travis AFB. Apparently this will not work in wordpress.
Can anybody think of a way to structure my categories to get around this limitation?