Just 10 days before the events of 9/11, I was on a mileage run, and my ORD-LAX flight was diverted because of a fuel leak. It turns out that it was a very BIG leak, as we had to land at small town in Utah. While this problem was serious, it wasn't as serious as your unfortunate situation, obviously!

As far as compensation is concerned, about a week later, I was sent a letter from United apologizing for the inconvenience. There was no compensation. And frankly, after the events of 9/11, I would have felt silly requesting any! (and my apology letter was sent on 9/10, so the WTC tragedy had no bearing on UA's decision).

You can read the details of my adventure here:

http://www.flyertalk.com/forum/Forum81/HTML/002100.html