I can do this with iPhone 6 already. And could do with iPhone 5. In a 2013 model year car. There is an USB port in my car, connect lightning cable and thats it: phone is charging, music is playing.
But then you have to rely on the car's data USB port supplying enough current to charge the phone while the audio + GPS are draining the battery. That's not always a sure bet, depending on the particular car's specs.
Other phones have separate ports for power and audio out, so they can charge from the cigarette lighter with more power while still playing audio and GPS through the speakers.
I have 2x Dodge Caravans 2005, and a 2000 Miata. Luckly the vans have AUX ports along with the mid-vehicle 6 disk dvd player. No usb, bluetooth, or tape deck.
