Well, that particular shot was done one of 2 ways.

1. Using that "psuedo-volume" cloud plugin for Max.

2. Simple compositing with the animated opacity of cloud layer footage combined with multi-planing.

If you are looking at doing the types of cloud work that was done for "Die Another Day", then might I suggest www.artbeats.com
as they have a fantastic array of all types of cloud footage to use for compositing.

Other than the Digital Nature Tools set of plugins from Arete.
https://www.areteis.com/products/maya...e/overview.htm

Other than the "VolumeGas" plugin at Highend, There really aren't many plugins or scripts available for Maya.
(only compiled for Maya 3 I think, not sure tho)

You could also use the PaintFX clouds brushes attached and/or painted onto curves and/or geometry allowing your objects to fly through.

Another thing I might try would be the tut at 3dtreat, as it's got some good ideas