I would like to know if it is possible to play a DVD using the AVIC D3 DVD player, while listening to the radio tuner, or iPod.

Before my AVIC D3, I owned an AVX-7300, which allowed me to do so, using a y-video connector. I was able to have a movie playing in the background, or the tv (with Pioneer TV tuner), while listening to the radio or iPod.

Can anyone confirm if this is somehow possible with the AVIC D3?

I don't believe this is possible on the D3, you can only select one A/V source at a time.

This feature is called dual zone, and the D3 does not have it.