Did anybody already see or did it already use this?
Terrain Shader

It says that allows you to adjust blend ranges, textures, light positions and shadow lengths. You can supply up to 4 different textures to blend at the positions you specify. Then simply hit render and Terrain Shader will do all the work for you! It lightmaps all areas on the terrain, blends the textures, and outputs a single colour map as a bitmap file for you to use in your own creations.