Attached Link: http://market.renderosity.com/mod/bcs/index.php?ViewProduct=66035

 I know it's more snow than cloud, but I can't see why you couldn't play with the transparency.  This shader is by Synthetic, and $8 might be more money than you want to spend for one shader, but it's there ;)

Sitemail | Freestuff | Craftythings | Youtube|

Knowledge is knowing a tomato is a fruit. Wisdom is not putting it into a fruit salad.