This is just an offering up of a mod over at TEXNexus that adds modular huge slabs of cliffs, peaks etc to make mountain slopes for various land settings including desert and arid.

Please feel free to download them and do anything you want to improve them.

http://oblivion.nexusmods.com/mods/44192/?tab=3&navtag=%2Fajax%2Fmodimages%2F%3Fuser%3D0%26id%3D44192