CodeProject: WPF C# Ribbon Control Library. Free source code and programming help
This article presents a library for producing Microsoft Office 2007 style ribbon interfaces; while the included source and binaries are in ALPHA release, it should be possible to implement even the most complex of ribbon style interfaces (albeit with minor alterations). Currently the library does not support creation of ribbon controls via WPF XAML code, however requires the creation of the ribbon bar via C# code behind.
A Graphical WPF Ribbon Control Builder – An article presenting Ribbon Builder, a tool for creating ribbon controls