Where did you hear that they stopped using the 7970 PCB? My second TFIII 7950 is a "Boost" Edition /w a 7970 PCB. My first one is a non boost, but still a 7970 PCB.
Keep an eye on Amazon too. They are currently out of stock. But keep checking, when I got my second one Amazon was OOS about a week before I ordered.
You can also TRY Amazon Warehouse. Just fair warning, Amazon Warehouse does not check the card when they get it back. I ordered a "Warehouse" one that was "like new" and when it came, the box was a 7950 but the card was a 5870 TFIII.
Oh one last thing. If you do happen to get a TFIII "Boost" edition. I would highly suggest you flash the standard "non-boost" bios onto it. I have been having some issues with my setup, lowish FPS, lowish bench scores. i.e. not BAD, but felt like performance should have been better. Finally I noticed in GPU-Z on the second "boost" card, the core was constantly and rapidly going between 880 and 960. Even if I OC to 1000, it would still go between 1000 and 880, where my standard card would just hold 1000.
So I flash it, and everything just better. It now holds 1000mhz core while gaming, FPS and Benchmarks went up.
Firestrike /w Boost Bioshttp://www.3dmark.com/fs/176437
Firestrike /w Normal Bioshttp://www.3dmark.com/fs/176615