The dream of putting HDMI content (Blu-ray player, Xbox 360, PS3 or even another computer) into a 27-inch iMac has FINALLY come true. Kanex, who have done MDP to HDMI adapters, now goes the other way with the upcoming accessory.
The bad part is that the device will cost $150
, and you still need separate Mini DisplayPort and HDMI cables (it's just a block). But it does support HDMI 1.3, DisplayPort/Mini DIsplayPort 1.1a, 1920x1200 resolution (that's enough for 1080p) but only 2-channel audio. It's not a bad solution for using the iMac as a display when that's all you have—like if you were a college student and had no space for a separate TV. You can use it for the other recent Apple displays that take MDP as well. It'll be available some time in April-ish. [Kanex]
Update: The guys at Apogee tell us that the box will come with all the necessary cables, which include a male to male HDMI cable, DVI to HDMI (both male), mini DVI to HDMI (both male), and displayport to displayport (both male).