The first batch sold out quickly from GW, but is now back in stock on their US site at least!
So glad as I was bummed that my local GW store did not get any copies and that I had to settle for the soft cover. Well, that one will be sold at a good discount and the hard cover ordered!
I don't see the Leviathan in hard cover back up yet, but I already got my copy to that!

[url]http://www.games-workshop.com/en-US/Shield-of-Baal-Exterminatus[/url]