I just uploaded the slides & sample application I used in my webinar on SharePoint 2010 Ribbon Customization Deep Dive by Critical Path Training. The download is available from the Critical Path Training site's Members section. To access this section you'll need to be logged into the site. If you don't have an account, feel free to create one... they are free! Once in, go the the Presentations section and it's listed as AC's SharePoint 2010 Ribbon Customization Deep Dive Webinar.