Longest Soundtrack ever?

I am very interested in soundtracks of games and movies. So I have listened to and owned quite a few of them. Most complete soundtracks that are available somewhere are about 2-3 hours. The official Skyrim OST is 3 CDs and the Portal 2 Soundtrack is 6 CDs. But the complete Skyward Sword soundtrack I found on a fan site is over 12 hours! Is it the longest game OST ever made?