I found a really interesting tutorial by Jonas Ussing

Jonas employs a nifty technique here to achieve realistic light scattering (which you can read about on the link).

In his words “…the photorealistic look of a cloud is dependant on decaying, non-polygon lighting”.

I’ve half a mind to either a) recreate The Simpsons intro in 3D or more likely b) stick my “ballet” character in the scene, flying around with a cape.