Jeff and Steve,
The PGP community represent a set of users who want to be able to
prevent the disclosure of their public key.
Speaking personally, while I support the idea of non-disclosure of the
public key, if I thought it represented unnecessary complexity I would
vote against it. Let me observe that the ability to do this "falls out"
of the chosen identifier mechanism, in particular arbitrary key
selectors, which, as an implementor, I assert represents no additional
complexity over choosing a particular key selector.
I will respond to the "hash" mechanism in a separate note.
Jim