31,000 US miles in case anyone doesn't have their metric>english converter up & running.

Sure it is. It's not common for a clutch to fail that quickly, but it's possible. You seem to have eliminated every other possibility for your symptoms (IE pushing the pedal to the floor moves the slave cylinder as far as would be expected) so the only thing left is a failed clutch. There is no way to find out more without dropping the tranny.

You will probably find either a totally failed pilot bearing or a pressure plate spring that got really hot, maybe due to a failed throwout bearing.

How hard you run your rig can be a factor, but sometimes these things just happen....

Dave