On Thu, 12 Jan 2012 18:23:45 +0100, Pieter Praet <pieter@praet.org> wrote:
> +			'face (cond
> +			       ((notmuch-show-found-target-p message-id t)
> +				'notmuch-show-buttonized-link-present-and-unread)
> +			       ((notmuch-show-found-target-p message-id)
> +				'notmuch-show-buttonized-link-present)
> +			       (t 'notmuch-show-buttonized-link-missing)))))))

I like it, but worry a bit more about the performance (we're up to two
'notmuch' invocations for a missing or read message).