Sync of Outlook PST file contents

I would love to be able to sync the contents of two PST files by examining the folder structure within the file and showing me differences. I think of it as similar to how ZIP file contents can be diff'ed as if they were just part of the file system. Any chance this could be generalized (ala viewer plug-ins) so that other special file types could have their contents sync'ed like folders?

[Craig]

We are planning on adding plug-in support for additional "archive" types in an additional release (not necessary soon). I don't think we'll support PST files ourselves, but it would be possible for a third-party to do it then.

I don't have any specific references, but there are a few products out there designed specifically for synching PST files, too.