It seems a bottom toolbar like the iPad app, customizable so we can choose what we use the most, and black, so it is less distracting, is a good idea.
Some other things that could then be in the toolbar:
views - like almost smart groups? View all txt, rtf, …, recents, flat list of all items alphabetical, … All that would be helpful without needing to go back to the main screen.
probably other things I can’t think of at the moment. I’d prefer to stay within a particular database than have to go to the main screen to access things like search, unread, …