This project aims to create new regional textures, particularly for the Southern Hemisphere. This is a project on development, so use it at your own risk. I would suggest backing up your Materials and Textures folders since some of those files will be overwritten.
Development thread: http://forum.flightgear.org/viewtopic.php?f=5&t=26031
By Gilberto Agostinho (gsagostinho).