Peter: I've already implemented this function (should be at the end of the file template)
Of course, we will have to do this not only for new submission but also for old (pre-implementation) ones. But we should get through it somehow
By the way, you can edit the special page header page ("IMSLP:Special:IMSLPEditCTag/MainText") and add information about the usage of the special page.
By the way, if the "Status (for admins):" bit doesn't show up, try purging the page cache by adding "&action=purge" to the URL.
Emeraldimp: Even though this time I dealt with it (because it is basically a copy of the Ratings page structure with detail changes, and so me doing it would be more efficient since I know the code base very well), I assure you that your programming skills will certainly be in demand... as soon as some sort of official coding project page is set up (as Peter was proposing on Leonard's user talk page).
Carolus: The popup is not that hard to implement, but I'm not completely sure of the effectiveness of a popup... many people have popup blockers (which may break the page entirely) and most of the information is already on the page per se. However this may be worth a try in due time (currently the coding "projects" are piling up high on my user page haha)