I don't know if this has been spotted before, but I have figured out how to take (E-mail Address not Verified) off the end of your passport sign in name without owning the actual email address.
1.) Sign up for the passport at www.passport.com
2.) Sign in using it on MSN Messenger, and click the popup saying "verify this passport"
3.) Click to change the email address associated with your net passport, and change it to something random
4.) Sign out of messenger and sign back in with the changed address
5.) Click to verify it again, and change it back to what it was originally
6.) Sign out of msn messenger and sign back in with the original email address.
Bingo, the (Email address not verified) is gone. You still can't change your name from the email address though, it just takes off the tag.
EDIT: I have just realised that this only takes the tag off at your end so to speak: you see just the email address but anyone you talk to or add still sees the (E-Mail Address not Verified)