This was one of the features I had envisioned as part f the whole smiley manager thing we chatted about in the other thread. You know, that expensive smiley manager? Except an admin can allow access to user id to drag and drop a smiley they use into a box where they title it, and then it automatically uploads afterwhich an admin or staff member is alerted of this as it will go into moderation to be authorized ensuring its suitable (size criteria, websafe etc).
I think you'll be waiting for a long time. It's something you'll maybe have to request or get built if you have your own specifications.