I tried to get one from Volkswagen at the time I ordered my car, but they supplied the standard iPhone one.
I couldn't find one, so if you do, let us know how you get on.
I was surprised at the bluetooth functionality being a tad sparse as well. Doesn't even detect text messages or anything. If I try playing normal mp3s from my phone (not Spotify) then it works (on bluetooth I mean). But the cover art/playlists etc. didn't. It would just skip to the next track, that was it.
VW must have shares in apple or something!!!