I'd be really interested in that too, but I just don't think it makes sense that we should find a way to do it in Vanilla, as this would be quite much more easily done if only the object could  do that on its own via messages. 

We're basically after a kludgy and hacky way of working around the object limitation, but I think the most elegant solution is just to make [clone] be able to do that. That's actually about the same issue I was having, which would be changing an object's parameters/arguments (in that case [filledpolygon]), but then, again, I don't think we should bother in that direction, but just work on making the object more versatile.

So maybe make a suggestion, open an issue, try a Pull Request ;)

cheers