I think if you wait long enough it will come out of the hang state.
I ended up returning my machine. I got a replacement and have not opened it yet...I'm in two minds whether or not to keep it.
So same thing happened to me, just after Christmas. It finally came out of the hang state and functioned normally... at least for a while. One day, everything froze up except for the mouse cursor. I could move it around, but nothing else worked, including force quit. Suddenly, it shut down and restarted on its own. When it booted back up, it started as if it were brand new out of the box. I had to set up the computer as if I just opened it, and once set up, all of my files were wiped clean. All preferences and settings were put back to default. However, all of my apps that I installed were still there under applications (although they were gone from the dock, which was also reset to default settings).
I took it in to the Genius Bar and they ran their tests. Everything passed fine. So they said they would keep it for several days and run some more stress tests, which of course also came up with no issues. So they told me to come in and get it and keep an eye on it. That wasn't acceptable to me, so after speaking with the store manager for a while, she allowed for a full replacement. I just got home from getting this replacement and am in the middle of setting it up. Guess what? It's hung on the FileVault Disk Encryption screen.
Ugh... This is killing me. This computer is for work and I already lost everything I put on it the first time around. Fortunately, it was only a few days after opening it up, so I hadn't transferred all of my work from my old computer just yet. But what if that happens again on this new one in a month or two from now? I can't risk that.
Not sure what to do at this point as I'm sure Genius Bar will be stumped as well. I'm gonna have to call that same store manager again and see what she suggests. I'll post an update if anything significant comes of this.