That week is Pop Warner football and a huge cheerleading competition at the Wide World of Sports complex, so the value resorts are booked solid. Although the resorts are full, the parks will not be greatly affected as the competitions take place during the day. I think the MK gets busy in the evenings, but we are planning to attend MVMHP on 11 Dec and then steer clear of the MK at night the rest of the week.
Try the travel agent from this site, Kingdom Konsultant. The owner, Pam VanSyckle, is a friend of mine. She might not be able to do any better, but her staff will monitor for an opening whist you are working. They've always done a fantastic job for me and I highly recommend them.
I still have not secured airfare for Dec and it is driving me crazy. The price of oil is down and the flights I want are only 20 - 25% booked. The airline will have to drop the price to sell the other 75 - 80% of seats - I just wish they'd hurry up!