Don''t know if Curriki.org (Curriculum + Wiki) has been mentioned on this list before?
Here's a blog post with a good half hour interview (mp3) with the head.
http://blog.curriki.org/2010/08/24/what%E2%80%99s-the-future-of-curriki-an-i...
I'm almost moved to suggest that the WMF could offer them some money, but I feel an opposing sense of vicarious greed. I'll be keeping an eye on the project, perhaps you will too.
I've often wondered if there was a way to have more of a virtual classroom experience as if you had lessons in a subject over a year. I've done a little (a very little) research into the UK curriculum. I think that schools differ to an extent that one will never find a model curriculum; there are certain things that *must* be covered but the manner of doing so seems rather open, particularly as the UK government has made the stupid and retrograde step of allowing faith schools.
I know we have topic outlines on Wikipedia which you could equate to some degree with a course. And there's Wikibooks. I won't mention Wikiversity as Curriki is for K12 and they don't yet plan to cover further education. Some of our templates, too, give a kind of course vibe. Am I missing anything?