> 
> How hard would it be to setup an imap server on this machine, that uses
> the existing email corpus database, /home/gene/Mail, and serves it to
> any other kmail agents running on my local network?
> 

I am using devecot imap on the server at home and access the mailbox on that
server from multiple clients. There is nothing special for that.

You have to tell dovecot where your mail is and in which format.
usually I would configure the server side mailbox aside from the home
directory.
You could use imap to copy your local mailbox data to the server dir after
you set it up once.
This is in /etc/dovecot/conf.d/10-mail.conf

you can use anything like fetchmail to get mails to the mailbox and serve it
to all clients. If you have any other pop3 accounts. This is what I would
do. Thus you collect your mails in one mailbox and access them via imap by
any client.

I also had my mailbox set in the user home years ago and this was I guess by
default set by Kmail, but turned to be misleading.

However the flexibility of all this is so big that there is surely a way to
get what you want or get it really wrong.

I hope this helps