Ribbon Hero was built as 4 different Office add-in sharing a lot of code + a separate application. Crating add-ins for Office is really easy in Visual Studio. The code was written in C#. The UI for Ribbon Hero was built in WPF. That made it really easy for developers and designers to work together.
I'm inspired by this kind of application too - was it built using VSTO? Also how does clippy monitor the user's actions picking up what they're doing? If you could point me in the direction of any code that does this (preferably VB.net) that would be appreciated!