In fact, fire is a great manifestation of God's presence for the simple fact that it has no form or shape. You can't draw fire, it is amorphous.
But a drawing of Moses' vision from the cleft of the rock would be inappropriate, wouldn't it? One who didn't know better could read your response above and conclude that you'd allow it -- which I can't imagine anyone here would.The burning bush was in no way to be understood as a representation of the Godhead. It represented none of his divine attributes. The burning bush, like the back side of God's glory that Moses also witnessed, was a manifestation of God's presence and nothing more. The pillars of fire and smoke were not God, they were merely a manifestation of his presence.
As I'm considering it right now, I lean against the permissibility of drawing the burning bush. Surely the fire represents something about God's divine attributes?