It looks like there will be over 40,000 cards available at launch and the company has hopes of 250K cards being available by the end of the first half of this year. As the Catalyst driver team just released the 9.3 drivers and they usually like to release updates in the latter half of the month, it looks like previews using beta drivers should start showing up soon.
That should be enough quantity for most and for the Radeon 4890 to not qualify as a phantom product.
Currently in talks with the reviewing media who have the final production boards already, the decision will be made pretty soon. It all comes down to the Catalyst team and if they can deliver the required drivers ahead of schedule. AMD could also do a repeat of the 4850 launch, a preview but with beta drivers and the review with the final drivers.