That said, you can get a long way towards creating a campaign world by using the published material so far - ie the Dragon articles, DMG information and info pulled from H1, H2 & H3.
Admittedly you won't have an overall campaign map, nor a deep and immersive history, nor will you have everything you'd want if you'd written it yourself. But you will have a lot of great locations that can be planted wherever you want, you'll have a lot of history (although you might need to put it all together in a way that makes sense) and you've got plot hooks galore for your own games.
So, no, there's no official '4e campaign setting'. There is, however, a vast amount of information available that you can build one from.