Have you seen how the iOS 4 email client works? It's very good, very simple, and very powerful. If you were to borrow from that, most of your design work would be done. Here's Apple's overview: http://www.apple.com/iphone/features/mail.html Here's a tutorial video: http://www.youtube.com/watch?v=0EYO5pRiHhI
Thanks cb22.. any chance of releasing a pre-pre-alpha version to have a look?