The new car doesn't currently have a CD autochanger in the boot (although the wiring is all there so it's easy to do). I'm active on a couple of mini and bmw forums (Mini for historical reasons as I used to have a couple) and asked what the options were for ipod integration. One solution that has come back is quite interesting and I can't decide it's madness or a good solution.

There is an Alpine interface that connects into the standard BMW head unit for use with Alpine extras (such as their own CD changer, DAB radio etc) but it also has an interface for an ipod. However, to use the ipod properly you need an Alpine head unit, which I don't have. So this company have made an interface box that connects between the Alpine interface and your ipod and let's you control the ipod via the head unit and also have a CD changer in the boot (which also has support for MP3 CDs with ID3 tags shown as well).

It's neat, and relatively cheap, however it's all a bit beta tester for my liking as it's not been officially released. Still, there is demand for the parts so if I buy it and don't like it, I can always sell it, and still use the MP3 changer.