I started a new Sunset Valley file and wanted to redesign it to be more modern and have more clubs, less of a suburb. So I started with City Hall, which I made into the all-in-one building from Late Night and placed on a 60x30 lot.
Not much to show, since it's a rabbit hole. Uses fountains and a Late Night rabbit hole/floors, everything else is base game. 60x30 lot, I stuck it where the Library and Police Station were. You have to delete the park if you want to put a new lot (in Edit World) there, though. (You can put it back later). It will fit on the original City Hall lot, but it'll be positioned oddly.