Tests done with Blender's smoke simulator, internal render and compositing (gimp was used for the image).
You can the animated result here :
http://www.youtube.com/watch?v=0hF09YMnuKg
The smoke resolution is set to 64 (division), with high resolution set to 3.
A little more than an hour to bake, 4 to 5 hours to render the whole video.
