Marcia Mellow...
For "old lady" names - Hortense (Horty), Bernice
I always thought about naming a white Boxer Ruth, after the white dragon in the Pern series (I didn't name my white Boxer that, but I thought about it
)
For names that mean or connote white:
Latte or Leche
Guenivere, Gwendolyn, Jennifer and deriviatives (Gwen, Wendy, Jenna), or just Wyn.
Or Lily, from Longfellow: "White as the whitest lily on a stream."
Whitby
Albatus (Latin)
Waub (Potawatomi)
From this site:
http://dspace.dial.pipex.com/town/plaza/ge75/girls.htm
Bianca
Candida
Fenella
Finn
Kelene
Nuala
Rowena
Whitney
There are a ton of other names at that site, as well, that don't have anything to do with white
I do suggest spending some time with the puppy before making a final decision, of course. And be careful of what name you pick - I've read several discussions on training lists where those who named their dogs "Trouble," "Rascal," etc. found they were self-fulfilling prophecies :D