as most people have already said, it is a fake. I mean, if this was real, Apple most likely would sue whoever released the pics, etc. Also, if you look closely, you can see that the ports were pasted on.
Also, I was reading my 20th anniversary edition of Macworld, and Steve Jobs had said that media PCs have all been failures, and the Mac and a TV are "two different animals", and they shouldn't be integrated. You use a TV to turn off your brain, and you use a computer to turn it on, according to him. So I highly doubt that we'll be seeing a media center Mac.