http://stephenjameson.com/tutorials/faking-volumetric-effects/ Damn the link is down :( Thank you wayback http://web.archive.org/web/20100528163256/http://stephenjameson.com/tutorials/faking-volumetric-effects/
IF you make your maps bigger than in that tutorial, add a 4th cloud map, make that one really big and panning slowly, then plug it into mesh displacement. Apply the material to something other than a plane and you'll get results more like what your picture shows.
A classic question I'm sure. I want to make some nice looking clouds for a scene I'm slowly working on that's set high above the clouds. Basically floating island. So what's a floating island without some sexy clouds. How would I go about achieving this effect? Perhaps a non expensive method since I am slowly running out…