I looked into this ALOT. In the end I remember someone on b m w c o d i n g d o t c o m, finding a vendor in germany that would sell you a brand new CA key fob with the vin already programmed to it. You just had to show documents to verify ownership of that car with the vin# you were trying to order for.
Im trying to find where i bookmarked. But i want to say it was this website:
http://store.bmw-mini-mania.com/part/66129268488
I've completed an idrive retrofit in my e92. You can make the wiring harnesses by buying the contact pins and sockets and all that from bmw and just use some 18-16awg wire of different colors to help you out.