I've done it. I signed up for my second 50K race this year! The Antelope Island 50K on October 19, 2013. It's held by the same folks as the Buffalo Run, but it's a different course. I've been told that it's easier than the Buffalo Run, and by looking at the elevation profile I would agree. I'm really excited to do another 50K!
Now, to get to work on a training plan!