[Dovecot] Compressed mail archives

[Will Palmer]

Hello,
I have recently begun using IMAP to access my mails, and have found that
the size of my maildir is quickly getting larger than I had
anticipated. 
Googling around, I've seen a lot of messages related to compressing
individual messages in a maildir. However, what I'm really looking for
is a solution which will allow multiple messages to be compressed into a
single compressed file, while still allowing those messages to be
accessed via IMAP. The reasoning behind this is that most of my incoming
mail consists of many very-similar messages (for example, it is not
unheard of for me to receive 10,000 emails detailing the same error
report over a weekend, with the actual "needs to be processed" parts
stuck on the end of each message)

I'm expecting a simple "no, there's no way to do that", but I wouldn't
mind being pleasantly surprised. My question again:
Is there any way to keep a bundle of older mails compressed, so that
they can enjoy the high compression of being very similar to each-other,
while still allowing access via imap?

A solution may involve (just throwing out ideas here, which I have no
idea how to implement) putting messages older than N days into an MBox
file, and either somehow linking my account to that file (so that my
account consists of [compressed readonly Mbox]+[live uncompressed
Maildir]), or perhaps the first half of that, but accessing archived
messages through a separate account. (Not the preferred way, but if it's
the only way, I'll do it) But really I don't even know if it's possible
to have dovecot support MBox and Maildir simultaneously, nor do I know
enough about the MBox format to even know if the IMAP-style "multiple
mailboxes" thing is possible in MBox.

Please excuse my no-doubt confused terminology and general air of
doesn't-know-what-he's-talking-about. The internals of e-mail are
generally not my thing, so I'd appreciate any pointing in the right
direction which anyone may have to offer.

Any ideas?