So, there will be one new "King of the Hill" this fall, a 2-hour finale.
http://artsbeat.blogs.nytimes.com/2009/08/10/yep-king-of-the-hill-gets-september-finale/
According to this article: http://blog.zap2it.com/frominsidethebox/2009/08/king-of-the-hill-abdicates-throne-in-september.html
there will be 4 unaired episodes. No word on plans for them, though. I suspect they'll show up on DVD, but who knows?
-- R Flowers