I am having the similar issue. My order was placed after yours on 11/18, I confirmed it immediately. I got an e-mail from Tesla saying that my order was confirmed. Eleven days later, I got another e-mail from Tesla saying again it was confirmed.
My car went into production on 12/9 and on 12/10 the dashboard said that 5 of 5 tasks were complete. I called the delivery specialist and she said that it should be off the production line in 4-5 days. Eleven days later, 12/19, it is still saying it is in production and 5 of 5 days are complete. To make matter's worse, my delivery specialist just quit last Friday to accept another position. I was told that I would get the car before the end of the year but it is looking like that may not happen.
Before I ordered the car I asked the deliver specialist could I get the car before the end of the year and she said yes. I told her if it was not possible I would wait to December to order it so I would get a 2017 instead of a 2015 Model S90D. Looks like I may not be able to write off the $7,500 until 16 months from now and I will get a 2016 instead of a 2017.
I looked at the Model S delivery spreadsheet and cars before and after mine was ordered have delivery dates.