I too was told sold out. 11/16 and 17 are, in fact, blackout dates, so I asked for 11/20. This was yesterday afternoon. I called back and the 2nd CM got me right in for the 20th.
And just keep calling. Hopefully they have it up on the webpage soon, so you can check quickly if a slot opened up. I can navigate to the link, to the party, by clicking on it in my itinerary. But the page just reads "Had to Duck out" still. And a search, on the Disney website, still only yields just the Jingle Bam show. The dessert party has yet to show up.
I assume no adult beverages inside the Magic Kingdom dessert parties. Is that true? If so, I am very excited about this being a new show with adult drink and tax and gratuity included! And no worries about finding a spot to see it. Epcot would be nice but I have seen illuminations many times. The Cruise would be great, to watch Wishes from the lake, but that is more expensive. So this is perfect. Plus, I never have all that much difficulty finding viewing for Illuminations or Wishes. I am not so optimistic about this show.