Reporting old / unused Virtual Desktops

I know Quest is working on some cool reporting features, but for the time being, can some help me with this?

I want to make a report that shows all virtual desktops in vWorkspace with the last time it was accessed.

Something like:

We use persistent sessions, so a user is locked to a virtual desktop.
Over time, we added a lot of users. We know some users only logged in once, but never used it again.
This way we want to cleanup the old/unused one's.

Does someone has a nice sql statement that can make such a report?