I like this last one the best. Fabulous... Looks very natural.....

Are these metablobs or Vue generated rock objects?

I've been trying to reproduce your mat but have been unsuccessful.  I couldn't make those metanodes I guess or crossed my vectors or something lol......I need to study more.....

But here's that squarish cliff object for you to try it on if you wish. Made in Metasequoia, voxelized and exported in 3dCoat and then optimized in Meshlab.....

www.monsoonsky.com/MetatestOpt.zip

I really like this render....