Although if same last names were possible as long as the first was different, if anyone uses mine, well... see you at Christmas I guess. Will be expecting pie.
(Although the maiden name I thought up for my Belf's mother turned out to be a last name used by one NPC, same race, so... well, I guess he's a cousin, my Belf usually /hellos at him when I'm there.)
Same last names would be cool to mark some of your own characters as related though.