BerconMaps

BerconMaps 3.* are licensed under Apache 2.0 license. See copy of the license in Source/ folder.
Contact information: jerry.ylilammi@gmail.com

You might also want to check out MultiTexture map that is supported by BerconTile to use randomized bitmaps as tiles.
Find it at http://www.cg-source.com/multitexture.php