I've had some clutch discs do that to me before. No warning, just ripped off and now we're not moving. By and large, you get what you pay for with clutches. Pull a transmission at 50k miles some time just to look at the disc, you'll probably be surprised at some of the things you see.

As for the pilot bearing, check your input shaft bearing for play. They cant work together at failing, especially if the one has gone out and been that way. It's quite possible you've been running with the pilot bearing backed out for some time now.

'97 T-100 SR5
'86 Toyota's, the variety pack (all gone)