I don't know that you will find anything soon. Part of the reason why Apple have changed their connector is that too many cheap manufacturers have been making things for the old iPhones etc, some of which actually cause harm to the phone. In an attempt to change this they have changed the cable.
And if my understanding is correct, the pins on the new connection are dynamically assigned between the phone and the device upon connection. So, music may be played between pin 1 and 8 the first time you connect but this could be pin 2 and 7 the next time. Apple plan to only release the algorithm on how this works to a select number of manufacturers in order to better control the supply of aftermarket accessories. I would have thought that BMW will be working with Apple on something, but this is likely to take some time as BMW will need to incorporate this algorithm into their stereo systems.
This article discusses the chip and why China cannot copy the connection at the moment... Cheaper iPhone 5 Lightning cable adaptors not coming any time soon | News | TechRadar
Personally, I would opt for the Apple converter for now - you could be in for a long wait otherwise...