Cross Platform Email Client?

AndrewRF asks: "I was wondering whether there was a good cross-platform email client that shares a common format for local mail, preferences, address book, filters, etc. files. I split time between a Win32 environment and Linux and collect mail from 3 different POP servers. I frequently find myself needing to boot out of Linux to retrieve a message downloaded by my Windows mail client that is stored in some non-accessible format. I've tried leaving the messages on the mail servers, but it's not as seamless as I would like. What I would really like would be have both platforms share a single, common set of local files. I've looked around, but haven't found anything that does the trick. I suspect that I could do this with Pine, though I'm ideally looking for something more GUIish. " To my knowledge, there is no such animal, although I wonder if there is a way to do this using external tools and scripts on both ends. Your thoughts?