Seems like after pressing CTRL+SHIFT+T in some of my cities a new Great Wonder slots appear. City may built additional Great Wonder, even if it could not before pressing CTRL+SHIFT+T. BTW. I use CTRL+SHIFT+T because a game does not notice that after expanding cultural borders a city is connected by water route with my other cities (when my civilization is at Raft Building level). Also Department of Water does not add Water Pipes to a city that achieved access to a fresh water (but did not have access when Department of Water has been built). I use currently SVN 10193.