I did this awhile ago out of boredom (while not playing minecraft of course), both as a fan project and as a challenge to see how to best redesign the website. Part of my thought process was that basically, one of minecraft's key appeal lay in the creation of your own structures, which is why I designed it so the background could be swapped around / faded every once in awhile. That was fun though NOTE: This is not an official redesign, it is just a personal project (read: for fun). All assets, contents and the minecraft symbol/name remain property of Notch and Mojang.
Uploaded an alternative background here: [link]
PS: Download it
) Much nicer quality.