I would settle for saving emails to the card and more databases as well. I know some 3rd party developers are working on the database part like WebIS for PI for BB.
I use a drug book application called PEPID that installs the majority of the application (4 mb) onto the card.
If they can figure out how to do it I would think (hope - pray) that others could as well.
This is about the ONLY thing I miss from my Treo.