I've got one of the original fat 60gb PS3s that was backwards compatible (purchased July 2007) and the 3D update (v3.50) works fine for me. I watched some of Monster House and all of Bob's Big Break from the MvA disc and everything played fine with nice depth and pop (better than my BD-6900 at first blush). I've got the PS3 connected to a PN63C8000 via a high-speed HDMI cable.
Could it be there are multiple versions of the MvA disc out there as was the case with the Panasonic 3D promo?
Xbox Live: XboxPhantom