Gizmodo has some video tests shots with the Nikon D90. Interesting to see the depth of focus, as well as focus problems (there's no autofocus in video mode!), and the reviewers note about problems zooming smoothly and that a tripod really makes things easier.
No, an SLR isn't going to replace a video camera perfectly. At least, not this one. And probably not the Canon 5D Mark II either.
Meanwhile Amazon had been accepting pre-orders for the Canon 5D Mark II, but now it says it's not available, and you can be emailed when it's available. B&H doesn't seem to be taking orders either, though it says that arrival is "Approximately November." Of course, if the economy grinds to a halt next week, who's going to care?