A coda to the saga of the cut-down Arduinos (a.k.a. Trinkets) that were failing upon being plugged in, and failing the repair process. I was not amused to read the Adafruit support tech's forum reply, which (paraphrased) amounted to "Try another USB cable."
Fortunately, I did have a spare on hand. No love, though...until I connected it directly to the Ubuntu workstation rather than the KVM switch that allows me to share a monitor, keyboard, mouse, and USB peripherals among multiple computers.
So the good news is that I might not have fried out a half-dozen microcontrollers simply by plugging them in for the first time...and now a couple of stalled projects are back on track. The slightly-less-than good news is that the repair process still blows chunks--albeit with a different error this time. (Ergo, if these things do blow out for real, I'm hosed.) The bad news is that the infamous "It works on my machine" syndrome is a thing in hardware even as simple as the Arduino.
But, for now, back to making stuff!