They said it couldn't be done, but Shantanu Goel has seemingly done it: married an Xbox 360 and PS3 together through some good, old-fashioned Kinect hackery. In the video past the break, you can see the first small steps for man that is Killzone 3 being played with Kinect. Yes, that is a sentence we never thought we'd have to write.
It's still a bit rough around the edges (a self-professed "pre-Alpha" build of the software), but the progress that Goel claims to have made is quite impressive to behold. It could be faked, but all signs point to this being a legitimate, working Kinect hack, using Kinect PC drivers and software that allows the PS3 to use PC controllers. Goel's posted a walkthrough online for all to see.