What's the cheapest way to get audio from shuffle to play in vehicle?

[blusubaru]

I want to see someone mod a USB port merge with a head unit. I'm not talking on the head unit itself where most manufacturers have placed them because those aren't iPod supporting, merely for flash drive use. I want to see a USB port on the top of the dash by the driver. Then you just plug your Shuffle right into the top of the dash and there's your controls. I don't care if the head unit doesn't show what the iPod is playing, but it should be able to charge the Shuffle. /end rant/