That's such an interesting concept! But it doesn't sound like they taste very good (according to this lady anyway): http://thevegasweddingplanner.com/2009/07/07/bedazzle-bon-bons/
I'm wondering if you couldn't use the colored cocoa butters that Chef Rubber sells -- I've seen bonbons done up with these colors airbrushed on them and they were every bit as spectacular. http://www.shopchefrubber.com/home.php?cat=1137
Based on her review, I wonder if they do use disco dust. That would explain how they don't taste very good. Disco dust has an awful texture, like eating tiny little shards of plastic. They get stuck in your teeth.
I know they say sanding sugars and luster dust, but I bet there is some disco dust in there too.