I don't think I like this idea. (Sorry Nuance.)

• First, links to users is probably translated when the comment is entered, and not at run-time (although I don't know, haven't looked at the code) so it would be non-trivial to implement
• Second, it would complicate the otherwise graceful simplicity of user links.

Certainly something in the users description (such as "Last Bio update: ") would be fine, but that wouldn't really give you want you want.