If you run Linux on your desktop you can achieve part of what you want at the application level. I run GPE PIM aps on both the tablet and my Ubuntu desktop. The files for these aps are sqlite and file compatable on both systems. I use calendar, contacts, todo and timesheet from the GPE family. On the tablet I also run erminig which sync with the Google calendar. If you will I use GPE on my desktop as a viewer of tablet PIM data. I handle synchronization at a file level over USB. Granted there are PIM aps available on the desktop that have more extensive feature sets but what I'm doing is workable without having to reenter any data. I use Gmail with IMAP access for the tablet and it's native mail ap, modest. That way I have one mail DB on the web. Not what the OP asked for but this particular mashup requires no new development.