I've given up and cancelled my order. Latest email from Dell confirms they have none in stock, and no idea when they will have stock. Very bad service from Dell, they shouldn't accept an order and give a delivery date if they have no stock.
"There is a delay in the delivery of your order due to a part shortage problem. This happened due to the huge demand for the INSPIRON MINI 9 systems, which we did not expect while advertising and hence the manufacturing facility have advised us of a change in the shipping date. However our factory is working with our suppliers and Dell will always try and improve the delivery date on your order. I am afraid I can't assure you a speedy delivery"
Perhaps they could have been honest in the previous emails I've had from them, rather than always saying it would arrive by 10th December. I could have cancelled my order a week ago if I'd known, and ordered something else. So, I've now ordered a Samsung NC10 instead.