After much searching:

Will the D3 run an external output (via the A/V out, audio and video) while running another source (XM, iPod) to the main speakers?

I have kids and would like to have their DVDs on in the rear, playing from the D3 (so the controls are up front) and still listen to my music from the D3.

Perhaps the Z1 or Z2?

D3 cannot multisource but the Z1/Z2 can.

Z2 rear screen selector has 3 choices:

MIRROR — The video on the front screen

of the navigation unit is output to the “Rear

displayâ€

DVD — The video and sound of the DVDs

are output to the “Rear displayâ€

AV — The video and sound of the AV

INPUT are output to the “Rear displayâ€

Thanks!