Have been looking for a device to enable proper iPod on the D3 and it seems that Alpine will soon launch this (http://www.alpine-electronics.co.uk/index.php?id=kce-425i ).It says that:
This versatile add-on solution lets you connect your iPod to a monitor in your car – and enjoy all your iPod entertainment, including movies! The black-box KCE-425i not only brings your current system up-to-date for watching movies, it gives you a gorgeous user interface that works similar to iPod, with same convenience and ease of use. Listen to your iPod music on your car system, watch iPod videos – even listen to audiobooks and podcasts, too. It’s the perfect solution for bringing the iPod into an existing mobile multimedia system
Looking at D3OC, there was a link to a video showing it working on a D3(http://www.snimci.net/video/kce-425i.html# )
This seems to be available from July and should cost £180.
I'm trying to understand all the features and will post back after I speak to the Alpine specialists, but if anyone has anymore information it would be great.
Also there is a nice iPod/Bluetooth product called eX-10 (will fit nicely on Defenders) with a small screen , check it out..(http://www.alpine-electronics.co.uk/index.php?id=ex-10 )