Have a look at the companies listed halfway down the page on http://danieltenner.com/open-cultures/ . Not all qualify as purposeful orgs, but quite a few do. Reinventing Organisations, mentioned on this page too, is a book that studies a dozen examples of purposeful, open culture organisations, if you're interested in learning more about this.
Those are just two companies, ran by the same guy. I think finding even a couple dozen more examples would be very difficult.