Hi,,
I think there is now a perfect solution from germany

It is "Dr. Bott Digital Video Link" (I know it sounds stupid xD)
Here is the link:
http://www.drbott.de/prod/DigitalVideoLink.html
This adapter just supports 720p, but it is confirmed that it works with the imac 27" and consols like the ps3. Also (!!!) the adapter can transport sound to the imac with Mini DisplayPort 1.1a and the iMac can play it(I even didnt know that this is possible) Again, the company confirmed, that it works.
Within the package comes the box, a dvi-cable (yes you can connect other dvi-computers as well), two minidP-Cable (one for 24"Cinema and one for 27") and that all for just 129 Euro/185 Dollar.
The only thing I dont know is if this lags (=bad for games)
I hope I could help you
Sry for my bad English, Im a Student from Germany
Update: Oh, the adapter also supports hdcp
I Think I will buy it next week and if you want, I can write a review.