I have been in consistent, productive conversations with Microsoft Customer Service, not Tech Support. As soon as the drive arrives back from DriveSavers, I'll call the other recommended providers and ask if they can do a "second opinion" free of charge. If not, I'll see if Microsoft will cover the cost. I think they may. They have actually been very responsive and very apologetic about what happened, though still maintaining that the damage was unlikely to be caused by the "shutdown" part of "shutdown and update." I realize no one is going to give me a definitive answer about precisely what caused the head crash, but so far everyone I've spoken with everywhere else other than Microsoft has acknowledged that removing power suddenly while a drive is in use can cause this kind of damage.
But to clarify, it's not that I want to sue Microsoft so much as I want whatever data recovered that can be recovered at no cost, if they will agree. So far, they haven't, and the one data recovery provider says nothing is recoverable. But that doesn't mean that a second opinion indicating that the damage could have been caused by removing the power suddenly but that some data is recoverable won't change their minds.
I'll let everyone know how this progresses.