Mailing List Filtering

I've been trying to come up with the perfect mail handling system.  I
started using ifile to detect spam and ham, and then using custom procmail
filters to categorize the ham into folders.  It became very tedious to
manage the custom filters, however, since I subscribe to over 50 lists at
any given time, and add or remove a list fairly frequently (as in at least
one a month, often more frequent than that).  So I decided the custom
filtering wasn't a good call, and decided to try and let ifile handle all
of the filtering.

Unfortunately, it's not working out that great.  Many of the lists are
similar enough in content that ifile often miscategorizes my e-mail.  What
I think would be ideal would be for ifile to put more emphasis on certain
headers, such as List-Id, which list servers use to mark e-mail as coming
from the list.  Of course spam is often filtered through these lists, so
that particular category will need to take precedence over this.  Any
chance of working something like this directly into ifile?

The other option is to use two systems, one that categorizes based on the
headers such as List-Id and ifile solely for locating spam.  But for this
I'd need a flexible system for list categorization. It can pick a default
folder name based off of the headers, but I'd want some way to automate
teaching the system to use a different folder, similar to what Jack
Bertram has done with ifile
(http://www.jbertram.net/projects/ifile/ifile.html).  This way I can read
my e-mail with any client and teach it new ways to categorize mail simply
by moving the mail from one folder to another.  I could code such a
system, but before wasting a few days on this effort, I thought I'd also
ask here to see if anyone knows of a solution like this that's already
been invented.

Thanks,

-- 
William E. Kempf