lol loving the idea of art designers "going rogue"!

like the design too, particularly the on/off button icon. and overlapping the default media player widget is a stroke of genius (closed source equals massive pain i believe! maybe not so much for media controls? i dunno.)! however you seem to have left out the RDSnotify status (or were you planning to have that hidden/ left in settings?) which would be a shame, specially with babel0 on board for the programming!

also with the size of the buttons and all 6 so close together this would be very difficult to use while driving, so not so good for the bigger n functional mock up, but definately fits into the small and pretty corner!