Animated Teaser for "A Dragon Lovestory". Feedback and tipps apreciated!

Hey blenderheads!

As announced I am going to share my attempts to get a teaser ready to show for the blBnderconvention 2011. My approach is to have more a “livesign” then an actual proof of concept. “Streifen” is my proof of concept :wink:

I had to change the original plan and removed the play-scene. A voiceactor, yet, failled to record his role and thus I had to change the whole concept: It won’t be a playscene anymore but a loose collections of impressions of the overall movie and characters… anyway: Here are renderings right from the first impression:

I could need some feedback regarding the background/fog

I would -love- to have some more detail in the fog. Clouds and stuff. Anyone an idea how that could be done? Tutorials? I would prefer to do the trick with the compositing tool instead with particles btw.