I had an old cadillac hearse one time with a 472 in it that just ripped the center of the flexplate clean out. I mean, the center was still bolted to the crankshaft, and the outer part was still bolted to the torque converter. It actually went with little drama. I was pulling out from a gas station, and there was a thump, then everything except park was neutral. I've also heard of some dodge trucks with the cummins doing that. I'd be curious to see what kind of failure your flexplate experienced.
'98 12v dually, 450 hp, 920 ft/lbs, ran 14.67 at 98 granny shifting the 5 spd, 278k