User creation - automatic subscriptions

[Craig Ringer]

> The user then needs to be subscribed to their mailboxes. This must be done
> logged in as the user - that is hard, I have no way of knowing their password.

This might be easily worked around using the ability of cyrus-SASL to 
authenticate one set of credentials and authorize access to a different 
user's resources. I don't think you can use cyradm, as it expects to be 
an IMAP admin, but you may be able to do it with a simple perl IMAP client.

I've used this trick with mailutil (from the uw-imap project) to great 
effect when migrating mailboxes from a previous IMAP system.

Craig Ringer