I would like to add that you really don't need the iDrive on your car or a module. You can use your rearview mirror instead. I would contact your local dealer and ask around to get a "rearview mirror camera" installed. Should be around $50 bucks or so. I googled searched it, and here's what I found.
http://www.alibaba.com/product-gs/51...r_monitor.html
http://www.alibaba.com/product-gs/48...MPERATURE.html
http://www.alibaba.com/product-gs/53..._with_USB.html
http://www.m3post.com/forums/showthread.php?t=643572
Let me know if you are still interested!
Thanks,
Edwin