Well it took long enough, but it looks as if Dead Rising has finally become available as an Xbox 360 Platinum Hit (in the States) with a fairly modest price tag of $US30. I made a few calls around and no stores seem to be carrying it yet, but if you want to get your zombie killing mitts on it now, you can do so through the Capcom Store.
I love Dead Rising and while many may disagree with me, it was a total system seller for me. It's a great game and if you haven't already checked it out, now's your chance to do it on the cheap. Just make sure you have one of them fancy HD TVs or a magnifying glass for that text. Ouch.