Dreaming, I will keep my fingers crossed that an opening appears for you. Please call WDW-DINE every day to see if any spots have opened up.
I was at WDW last Christmas / New Year's for three weeks. I had all three of the GF's childcare activities booked every week of that stay, and for "3" children for one of those weeks. When we arrived in WDW, our plans changed a little bit, therefore I wound up canceling a few of those reservations (and turning the "3" kids' reservation into a "1" kid reservation since my nephew & niece decided that they wanted to do other things instead). So, the moral of the story is to keep calling. People's plans change all the time.