Yes, I have been playing with fire! I have had this flame shader by NVIDIA (from the SDK) for ages now. I tried to implement in my olf RC3D Engine but it was a poor attempt and was of no real use to anyone, but I think I may have the beginnings of a decent implementation now. I have mixed the NVIDIA shader based on Yury Uralsky's "Volumetric Fire" with my billboard shader and billboard particle system and it seems to be playing quite well.
Take a look at the clip and let me know what you think.