This message is mainly aimed at Tomaz and Helen, but I could not see any harm in posting it here.
Obviously, there is a chunk of work to do to update the quiz and question bank documentation for Moodle 2.1.
My colleague Phil Butcher, who writes most of the quiz docs for OU staff, may be able to help. He points out that there is some stuff about the new system here: http://labspace.open.ac.uk/course/view.php?id=3484. You are welcome to take any of that for docs.moodle.org. If you want Phil's email address, message me. There is some other internal docs Phil is in the process of writing that you may find useful.