Would it be possible for all the default themes to be contained in a .dat file (or something similar) so that you could new themes easily and be able to tell instantly which themes (or maps) were not part of the default game so you can transfer them easily to a new version. Another way of this would be to create 2 new folders, one for new maps, and another for new themes. then when a new version comes out you would simply copy these folders and place them into the directory of the new version.

,Thanks