Probably not - I mean, how would the PS3 handle outputting a DVD like that? It could output it at 1080p over HDMI, but only 480p or 480i over composite. You'd need another frame buffer, and that'd get really complicated really fast.
Interestingly, the original design for the PS3 featured two HDMI ports - one of them might have been a pass-through, but there was some speculation at the time that you would see PS3 software that could output to two screens at a time. *shrugs*