I do not know the answer for a fact, but I doubt it. Surely cotton candy depends as much if not more on the, as it were, mechanical properties of sugar as on its sweetness. You would need a substance with the right sort of stickiness, viscosity, etc., and current artificial sweeteners are not formulated with that sort of thing in mind.
Also, artificial sweeteners are generally a lot sweeter per unit volume than sugar (that is sort of the point, so you don’t need to use nearly as much of them to get the same sweetness - few if any are actually non-caloric), so even if you could spin them into cotton candy they would almost certainly be far too sweet to be palatable. I suppose it might be possible, in principle, to come up with some sort of mixture of a sweetener with something flavorless (and perhaps low in calories) that would also provide the right sort of mechanical properties, but I do not think that that is what you are asking (and I have not heard of it being even attempted).
Last edited by njtt; 07-03-2011 at 06:35 PM.