[RacerBill]

Hmmmm... Smart Balance has more water than butter, so I think it probably won't be as gooey.

I'd be curious to see how the butter-free version comes out. I suspect the melted chocolate will sieze if you stir in the cocoa without any more fat. You might be able to get away with substituting a few tablespoons of a monounsaturated fat, like canola or light olive oil (extra virgin might give it an olive oil taste) in place of the butter. Won't reduce the fat content much, but it will be unsaturated.

Let us know how it turns out!