I've animated a few start menus. My current entry for the Christmas contest has an animated start menu - https://www.wincustomize.com/explore/windowblinds/7570/
You need the Pro version of Skin Studio. First, like most animations in Skin Studio, you make a series of images, stack them, turn them into a .tga file and save them in the Windowblind folder (you can do this using the subframe builder in Skin Studio). Then choose "Start Menu Animation Builder" from the tools menu, in Skin Studio, and use the drop down menu to import the .tga file onto the top of your menu image, fill in the number of frames, and play around with the speeds and margins until you like what you see, and save it.
A few of my other skins that have animated start menus are Theater Of The Mind, Zombie Outbreak (animated maggots), Hibiscus and Anoles, and Steampunk.
My gallery is here, so you can find them easily: http://k10w3.wincustomize.com/skins.aspx
If my day job's work load starts evening out, I will try to post a little mini tutorial on this, since it seems there isn't one that is easily accessible.