Just because Disney says it's sold out, don't give up. Big travel agencies get blocks of rooms.
We tried booking the December 31st cruise directly with Disney. They told us the cruise was fully booked in all categories. I called Expedia and Travelocity. Both were able to find rooms in the category we wanted. We ended up going with Expedia because they were able to get us five rooms in a row (mid-ship even).