Just in case someone might find it useful...
It seems that my port of the Mutt email client to MPE/iX works
reasonably well. I wouldn't call it extensively tested, but at
least I was able to access my Netmail/3000 inbox via POP and my
(shudder) MS Exchange inbox via IMAP -- from a terminal :-)
Find it at http://www.editcorp.com/personal/lars_appel/index.html
As usual: not HP supported, use at your own risk, Open Source.
Lars.