with dunes changing form and sand moving and flying in the varying degrees of WinD?
some hints for making are perhaps at http://www.cogfilms.com/ , parts about gathering storm.
http://www.compfused.com/directlink/760/ is a photo of a serious one..
http://www.megagames.com/news/html/screensavers/realsandstorm3d.shtml is a screen saver, no idea if it's any good - the screenshot looks awful.
http://www.plessinger.us/gallery/George-Thompson/aau is not too great either but shows already ok
this guy started by drawing on a tablet, seems nice - http://forums.cgsociety.org/attachment.php?attachmentid=74705
http://forums.cgsociety.org/showthread.php?t=288774 links to a small video where it looks ok
http://sorenworlds.netfirms.com/Wavy/wavyOcean.htm has .. wavy ocean