>  The point is that there are some mailboxes that are owned by individuals,
>  and they should be able to be used to represent the individual that owns
>  them...

Why do you care what kind of URIs people use to identify themselves? It
shouldn't matter whether they choose any of mailto, http, ldap, uuid, or
even urn as their favorite scheme as long as it's unique.

Are you trying to provide a "shortcut" to a person's mailbox where their
metadata isn't required to send them an email? I can see that as being
somewhat practical but doesn't that defeat the purpose of your experiment?
If someone wants to send an email to the person represented by
urn:person:Sean-B-Palmer then they should actually retrieve the
rdf:Description of that URI and check its me:mailbox property.

This brings up an interesting point: how will they find the rdf:Description?
Maybe an even more practical solution would be that the URI needs to a be a
network retrievable URL with an RDF file at the end of it.

Jason.