From:ShortYes@aol.com

 In one of the movies, Luna became a human being.  So why not Arthemis?

You're too late! Someone already wrote a fic like this. And he didn't bother
to turn Arthemis human first! You can find this one here:
http://anime.muck.com/~sakura/main.html Just look around a bit after you get
there.
Another suggested solution is to dip Minako in the Spring of the Drowned
Cat. Haven't seen anyone written a fic like that yet.