Apple's own Mini DisplayPort to Dual-Link DVI Adapter—the one you use to connect a Mini DisplayPort to a 30-inch display—has problems. These problems were never fixed with a software update, unfortunately. But Kanex thinks they can do better.
Kanex, if you recall, does MDP to HDMI adapters, so they're already familiar with the technology. They also tell me that their adapter is smaller than Apple's first-party ones, and does not have the display problem. It retails for the same; $100. [Kanex]