i have made a fairly good fat free whipped topping (it's a floor polish, no, it's a dessert topping!
) by using my immersion blender, aka a boat motor, in emerilisms.
i dissolved a little splenda in just a few ounces of fat free milk, then put the sweetened milk in the freezer for about 15 minutes. when it is just beginning to freeze over but not through, you blend in as much air as possible with the immersion blender's whipping disk.
the only problem is that it deflates quickly, so ya gotta eat it right away, not like that's an issue usually.
i think i'm gonna try to add a little gelatin next time to see if it helps stabilize it some. i wonder what will happen to freezing gelatin. my guess is is will not freeze as quickly as the milk, due to it's viscosity, so it should be ok.