This thought has been running through my mind all day.
A map (island) in the shape of a crescent moon. I've just watched "Naruto the Movie: Guardians of the Crescent Moon Kingdom".
You can read more about it
here (http://naruto.wikia.com/wiki/Naruto_the_Movie:_Guardians_of_the_Crescent_Moon_Kingdom).
Anyway, I don't know if you are experienced in making such maps and if this idea will fit your groups theme. Here is an image: