Thanks to Nath we can safely say this can be done provided you have the hardware and someone who can be bothered to use IDS rather than fobbing you off with crap like 'it can only be done from factory'
Oh and my personal highlight.... SPOTIFY WORKS OVER STREAMING inc track display!!! Oh I'm happy. Now to find a cheap module
This is for anyone who commented or took an interest in that mammouth 'USB can it be done' thread. Get ringing scrappies and talk to nath.
I'll second the above - Nath did mine as well and it works a treat. I'm over the moon with it.