Hexus published a small picture of the upcoming ASUS ROG Rampage III Black Edition motherboard. It has a X58 chipset and the main novelty is ThunderBolt, a new expansion card from ASUS that integrates Xonar sound as well as BigFoot's Killer NPU.
Pricing and availability is unknown.
Despite the launch of Intel's Sandy Bridge platform, the ultra-high end is still served by the venerable X58/LGA1366 platform, and it's that audience that the Black is targeted at. The spec-sheet for the board itself reads pretty much the same as last year's Rampage III Extreme, although there have been a few tweaks along the way, including redesigned heatsinks.
Basically, this means that the board sports a quartet of PCIe x16 slots capable of supporting three-way SLI or four-way CrossFireX, support for 24GB DDR3 at speeds of up to 2,200MHz and all the other high-end features you'd expect on a ROG board.