Some marketing: We are actually providing a Javascript wrapper for most of the official Outlook API, much more fully featured (incl. ribbons):
http://developer.yasoon.com/
Yasoon looks cool! Is it Windows-only? At work we run Outlook on OS X, so not sure if it's usable there.
Yeah, unfortunately it's Windows only atm. Outlook API's on Mac are basically non-existent, so we are having a hard time bridging these :/