I have written an indepth tutorial on how to create a procedural canyon material which includes the canyon wall, cracked mud and water in the same shader. It makes use of two bitmaps and vertex colour masks, together with a lot of procedurals to produce a detailed shader. Hopefully it will inspire people to play around with procedural materials and at the same time show that you can come quite far with them.
My version looks like this:
Get to the tutorial here:
Direct link: http://www.cgworks.com/tutorial.php?id=1[/b]