I was supplied the blue cable too, I didn't know any different at the time I picked the car up, but as I have an iPhone 5 with the new Lightning port I can't see any point in hassling my dealer for the red cable.
I've been using Apple's Lightning to 30 pin connector which works but obviously no album artwork.
It bugs me because all my music has the artwork embedded and the display doesn't look so nice with the grey square and a question mark on it!
I can't see any new cable from Audi with the Lightning connector solving the issue though as I assume the 500 pixel limit is a limitation of the system itself rather than the cable.
For now I've loaded up an SD card with music and use that, most tracks display the artwork except of course those where the image is too big. I don't fancy going through all my albums and re-sizing the artwork and I've not found any software that would do it automatically either so I suppose I'm just going to have to live with it.
I love the car though, which is my first Audi after 35 years of driving!
Cheers,
Steve