HDMI to Mini DisplayPort from Kanex

What you see here is the Kanex HDMI to Mini DisplayPort Converter that allows you the user to connect to any HDMI source device into a 27-inch iMac, LED Cinema Display, or any other Apple device.

It supports HDMI 1.3 and DisplayPort/Mini Display Port 1.1 a, and provides a maximum resolution of 1,920 x 1,200 for standard DVI, or 720p for gaming consoles.

You should be able to get it in April for $150.