Are you familiar with hypermail? It is an archiving program. It takes email and puts it in a convenient html archive. What hypermail purportedly does is take mail from mbox and put it in the archive. It can’t be too complicated or difficult to configure and install. Do you know anything about it? Would it work on your servers?
I am not very familiar with hypermail, but from what you describe the biggest problem would be that our mail server software (qmail – qmail.org) puts the messages in maildirs.
Another problem is that the maildirs are only accessible by the special user vpopmail. You can forward select addresses to your Linux shell mail account (your_username@your_server.phpwebhosting.com) and have direct access to the maildirs there to convert them to mbox format. However this becomes complicated and we are unable to provide technical support for it.
I would say the bottom line would be that if you enjoy messing with things a bit, you would be able to make it work. If you want it to just work right away, I would advise against it.
Underneath the control panel we attempt to provide as pure of a Linux shell account experience as we can. If you like developing in that environment then you can probably make what you want to work happen. However you would be on your own. We only are able to provide official support for the email configuration in the control panel (having said that, I personally send all my mail to the shell and read/manage my mail in a mbox-format with a shell mail reader – so it is possible).
I hope this has helped.