So. I got about 2 weeks worth of OK out of tLBN before it decided yet again to refuse to start. *sigh*. This time I got smarter and had it towed to the dealership where I purchased it. I figured if they couldn't fix it, I'd guilt-trip them.
Well, I ended up having to rent a car for one day, but I finally did get them to fix tLBN, and it's worked fine since. Broken wire in the wiring harness to the starter.
Seriously expensive repair, in all, but at least it works now.
Another post a little later on more recent things.