I am actually pretty amazed that this guy has never popped up since 9/11. There have been a few supposed sightings in Latin America but I have not heard about any ops that were linked to him.
He may be liasing with groups like FARC but I tend to think he is no longer alive. I am sure there are plenty of very soft targets in Latin America to hit if that was his goal.
Everything on him is pretty sketchy and he virtually disappeared of the radar for a good year or so. There was a reported sighting in the last month or so in the southern U.S., and then the Sun (UK) reported that he could be in Britain:
http://www.thesun.co.uk/article/0,,2-2006480097,00.html
Prior to that you have to go back to last summer when he was believed to have attended a terror summit in Waziristan.