Particles could be another possibilty to check out in your quest for realistic fire. There might be a preset you can alter to taste. You can have both fire and smoke "emitters". I don't know if the particles can be pre-rolled to start before the first frame of an animation, but it would be fairly simple to set up a time line, arrange several fire and smoke emitters and then scrub the timeline to the point where the preview shows that everything is emitting and then render just that frame, or the whole animation if you want.