Access MVPs Gunter Avenius and Peter Doering have setup a site with information on ribbons from Access point of view, with lots of VBA and XML samples. The site is online in English on
You might also take a look at my blog post a couple weeks ago. (I was surprised more of you didn't click on it.) It has a sample database and a few screen shots with ideas about how to design interfaces that take advantage of the strengths of the ribbon.