Here are the original retina wallpapers that came with my iPad 4.
It looks like a photo of the 12 Apostles in Victoria, Australia. Not what you're after, I know, but might get you closer.
Found it but it's only 1024x1024. No retina yet. Or parallax
Steeley, jonnyb, and tiggger you are deff bada**. Thanks for finding this then working on it.