My initial search turned up nothing...as did the dozens of other searches I made on the topic. Eventually, disgusted, I went on to other projects--which a few days ago, turned up the "
Warglaives of Azzinoth" mod, which, as it turns out, injects an additional "hidden" quest (with a spawnclass), that completes on accepting the Destroyers "Warn the Town" quest in Act 1.
Inspired by this method, I studied the game files, and quickly discovered that there is already a semi-hidden vanilla "start of game" quest, which also gets completed by talking to the Destroyer. And so, with a tiny amount of work, I was able to reduce the impact of the "Warglaives" starting gear method to only 2 files, rather than 3.