Lots of law schools (and other academic institutions) already use BePress to archive and provide journal-publication options. Features include tagging and updates much like you’ve described. (See, e.g., http://ir.lawnet.fordham.edu/flr/vol83/iss6/11/ )
Those of us who administer law-school BePress IRs get pushback from faculty who prefer to deposit exclusively with SSRN for various reasons. Today’s news will be an interesting addition to the mix of considerations.