According to FUD Zilla a power component is responsible for the shortage of NVIDIA GeForce 8800 GT graphics cards:
Sources have confirmed that Nvidia let everyone makes their own cards and that the Flextronics cards are slowly kicking in and that the market is beginning to recover from a huge retail / etail product shortage.
It is hard to believe that Nvidia has a lot of G92 chips to fill the shortages but Nvidia is out of power components that you need in order to make G92 / D8P based card.
Nvidia qualified only one component from a single vendor and these boys and girls cannot make enough of them. We heard that it is one of the power component on the card.