One thing we can't do using the default cloud setup is create offset clouds. Currently, the clouds flow in concentric layers around the main planet. This makes it difficult to make clouds that truly change vertically. The current system can do it in a way, but I discovered a way to make some radical looking clouds that are not bound to the planet.
Here is what to do: Create a second planet. Make the second planet's radius 0 (so its invisible), and disable its atmosphere (we don't need it). We are going to use the second planet's clouds on the first planet. The clouds will be offset relative to the main planet, as they will be wrapping around the second planet. Now place the second planet wherever you want - the clouds will follow it wherever you place it.
For example, put the second planet about 10000 meters away from the render camera. Make its cloud height 0, and its cloud depth slightly less than its distance away from the render camera. This makes for some crazy cloud effects, as the clouds are associated with the second planet (wrapping around it), not the main planet, but are effected by the main planets atmoshere and lighting. Move the second planet around to place the clouds in different configurations.
Some example effects: placing the second planet overhead creates clouds that curve "upwards" towards the second planet. Placing the second planet way out in front of the camera makes vertical style clouds that come out of the ground on the main planet. The options are endless.
Hopefully, someone can give this a shot and post some of their results. I'll post what I have when I get back home in a day or two. I've already tested it and it works well. I hope this wasn't too confusing as its just hard to explain.
We may even be able to do this with terrain, but thats another test and topic.