I've only just seen this thread, thanks to ZaraJoon's having woken it up with a link to Andrea Minini's wonderful work. I'm amazed to read, Matt, that you think (or at least thought 2½ years ago) a general purpose duplicate command with parameters would serve as a suitable substitute for blending between two objects, given all the things that you can't do by duplicating or power duplicating a single object. You only have to look at the controls for the Blend Tool in DrawPlus (position and attributes profiles, and specifying the path between the end colours) to see what I mean.