I saw the addon the russian developer put up in the resources, but it is not quite right (especially the price). I quite like the way vBulletin has made their comments nested in vB5, and I would really love such a feature to make it to Xenforo.
As opposed to quoting a user, you can click "reply" and it will place your comment within their postbit. This seems like a really great way to keep conversations neat and tidy.
Is anyone working on something like this?