ok, I fiddled with vnc. slow and a weensie tricky.

I tried a couple of mail clients, mutt (butt-ugly cli dealie), and sylpheed (compiled with a bunch of warnings but still runs)

I looked at requirements for spruce, GNUMail, balsa...
they all required stuff I wasn't willing/ready to install.

I think I'll go with sylpheed. It's certainly not the most feature packed email client, but it is serviceable from the point of my quest.

Sylpheed can import mboxes, so I can ssh -X to my home machine, launch Apple's Mail.app from the command line and then import my mboxes when I need to get my mail. Sylpheed also allows me to set up a default bcc for outgoing messages.
Sent mail messages won't get lost between mail clients that way.
Or I could export sent mail to mbox format, but...

I sure wish Apple made an X11 Mail.app counterpart, with wizzy spam trapping, that read wrote to the regular Mail.app mboxes.