cyrus-imapd works fine on my 43p 260.
I tested and suggest the following keywording:
=dev-libs/cyrus-imap-dev-2.2.12 to ~ppc64 (optional)
=dev-libs/cyrus-sasl-2.1.20 already ~ppc64
=mail-client/drac-1.12-r1 to ~ppc64
=net-mail/cyrus-imapd-2.2.12 to ~ppc64
=net-mail/cyrus-imap-admin-2.2.12 to ~ppc64
=dev-perl/Term-ReadLine-Perl-1.0203 to ~ppc64
=net-mail/mailbase-0.00-r8 already ~ppc64
thx for noting this. I can confirm that cyrus-imapd *runs* on ppc64. I've added
~ppc64 to all of your suggested ebuilds.