Well this is weird: Apple's gone and leaked one of its own products. MacRumors points out this image of a Lion-backgrounded Cinema Display that showed up today on Apple's website, along with a shot of two daisy-chained displays.
It was previously rumoured that product number "MC914" would be attributed to an upcoming MacBook refresh. As evidenced by the URL of this image, which clearly labels the Cinema Display as MC914, this turns out not to be the case.
Why replace mini-DisplayPort with Thunderbolt? The latter lets you plug multiple monitors into one computer by linking them into one another. Of course, this would only work on Thunderbolt-equipped machines. [MacRumors]