As above, I have just put one of these in my Golf:
http://www.halfords.com/sat-nav-audio/car-audio/dab-radios-car-stereos/alpine-ute-72bt-drive-less-head-unit-with-bluetooth-and-ipod#tab3
Amazing value for money for £70, does everything I want it to do. My only gripe is that you can't search your iPhone's music while connected via Bluetooth, but you can stream whatever you have selected on the phone, or search if it is connected via USB. I have actually ditched the phone for music and put a 32GB low profile USB stick in the USB port as you can then do everything (search, shuffle etc)