I use Thunderbird as my email client for Gmail from two different machines, so I have two sets of the same database (over 100,000 emails) (three if you count Gmail's dataset). If I add or delete an email on one machine, it synchs with Gmail, which synchs with the other machine. It works fairly well but not perfectly. Is there any way to make the "Local Directory" for Message Storage some kind of shared file rather than a folder on the local machine?