From:	Jussi Nikander [SMTP:Jussi.Nikander@alien.nixu.fi]

That's been done in a fic series "Aa! Megami-sensei" that's on the RAAC
archive. Can't remember who wrote it though...

The author was Peter L. Ward. He seems to have dropped off the net as there 
have been no new episodes in a year.
Back to the issue at hand, Urd would have to lose some of her seniority to 
go in as a student. I just can't see her doing something like that.