LO comes with a ribbon-like UI called "NoteBook Bar" from atleast an year. It's deployed as an experimental feature in 5.x, but I've found it stable. Perhaps they've made it a mainstream feature now in 6.
It would be cool for them to do a study.... have the default set to whichever version of the toolbar people use most in their settings. A real life, long-term usability study. I bet the ribbon loses big-time since it Is such a discoverability nightmare.