This doesn't exist yet so far as I know, but what do you think about adding SACD to cars? There are already 4 speakers at least, so the rears could be used as the surrounds. The fronts would have to form a phantom center. Most cars don't have subs, but that's ok. It would be nice to be able to hear SACD and DVD-A in that format when in the car. I see this coming in the future, especially since cars are coming with DVD for the backseat now...the DVD could be in surround as well.