A cheap auto escape hammer (IIRC, free in the bottom of a tag-sale box filled with stuff I could actually use) has been kicking around the back of the bench for far too long; it had a feeble single-cell incandescent bulb flashlight with the cheapest possible non-switch. I ripped all that out, carved out enough plastic to fit a CR123 lithium cell, hot-melt-glued a real pushbutton switch and 10 mm white LED in place, and soldered it up:
The CR123 puts out enough juice to light up the LED, but it’d be happier with a bit more current. There’s no limiting resistor, so the LED gets what it gets.
Augment the screws with a few snippets of Kapton tape, use some real 3M Velcro tape, and it’s all good (albeit ugly on a stick):
Now, there’s no way to test the hammer part of it (perhaps I could visit a junkyard and whack out a few windows for practice?), but at least now we have a disposable flashlight in the van…