Apparently so, as that is what SimWay picked up on!  The December issue of  Die Sims 3 Offizielle Magazin may include a tutorial on how to create your own neighborhoods…

The official text:

New Neighbors

Are you the boundaries of Sunset Valley too narrow? Then create your own neighborhood!

So if this is true, we should be expecting The Sims 3 Neighborhood Tool to be released within the next two months!  Of course we will have to wait until the magazine hits shelves in Germany on December 11, 2009 to confirm if this is true (or just wait until the November issue for more info on this matter).