I don't have FiOS, yet.
I just had a long chat with a Fios rep who insisted that all my 4 HD TVs can view HD content off one multi-room DVR, simultaneously. I did not believe it. But the Verizon employee said that it is true.
Can it be that a new hardware or firmware enabled multi-HD streams? The MOCA specs (above) and math supports it, theoretically.