and it does appear like the Monitor Audio unit takes digital out of the ipod.
I don't know; I seem to recall that Vinnie was very skeptical as to how they might achieve that, and why more companies do not do the same thing. You might write to him if you want to get his input on the subject. That said, my car stereo has an iPod interface that I plug into which requires a separate box to achieve. I don't understand what the box does and why the stereo isn't just taking the line-out from the iPod and amplifying it (why would you need an interface for that? Other than to get another $100 from your customer.). In the case of my car deck (an Alpine), the CD player does sound superior to the iPod playing the same material for whatever that's worth.