Has anyone seen this article from AnandTech, the quote below is from the last page of the article "Our Thoughts".
ASUS P5B: New BIOS Adds Unlocking & Improved Overclocking
ASUS has told us they are not finished with this "Conroe Unlock" feature and that they are working on BIOS revisions to also bring Core 2 Duo unlock to 975X chipset motherboards. We have seen hardware modifications to the Intel 975 BadAxe that allow unlocking, and it would be great if ASUS can accomplish the same with a simple 975 BIOS upgrade, as they have on the P5B Deluxe.
ASUS P5B: New BIOS Adds Unlocking & Improved Overclocking