I read one post in which the crafty owner affixed some sort of vibrator to the
key (in a desperate last ditch attempt to turn it to the #1 position to be able
to remove the bad lockset tumbler... and it worked)

Try Anything you can.WBAIN is correct. So's GILLY.

People who cannot turn the key have attempted to drill out the lockset...
(The damn thing must be made of some sort of NASA Titanium alloy)
50% / 50% chance of success [may be even less].