I was completely surprised tonight. I was able to book the HBD on the evening of 12/13/08, I got the exact time frame that I was looking for too. I have had really great luck booking ADR's for this trip, even at this late date!
Just remember to be flexible and in most cases, you can still find some pixie dust.
Persitance works, usually we stress over nothing because eventually something comes our way. So happy you got what you wanted. You'll love HBD the food is good, the waitstaff is friendly, Have a FUNtastic time