I´m re-posting this over here as the old forum content can´t be accessed anymore.
Here an approach to create stylized flames inspired by the animated movie Kung Fu Panda.
This solution uses particle geometry to create alpha mattes in the shape of fire. The look arises combining multiple variations in compositing. So it is basically a 3D to 2,5 D approach.
You can find the scene file over here. It should work across all XP versions and renderer engines.