@Remnant : As paul already said, I tried settling the sand in the cracks using the deposition map from erosion. Seems like the terrain should be at least 4k for that to look right, whereas I have to deliver not more than 2k maps, and possibly less than that. File textures need to be hi res for the proper megatexture like texturing, then maybe we can dial down on resolution. I may try it on some personal projects though, as this seems an exciting angle to explore. As for cranking up the textures, I don't have a very good texture library, nor do I know of many sites to download Hi resolution textures. I am a purely procedural guy, I build my own textures in vue or filter forge, although It would be too much work for a small project like this. Could you point me to a good site where I can find some Hi res textures in Creative commons domain?
@onkelpoe : Thanks, but I must mention, I got this idea from you!