I carried one very much like this
http://www.eastpak.com/uk-en/delegate-absurd-aqua.html
in lavendar through all 4 years (and 1 summer school!) and ended up giving it to someone when I didn't need it any more. I'd take durable over customizable any day, but you may be able to find something similar at LL Bean or Lands End that they can put your letters on.