Well, I finally did it. I followed the inspiration of cyclist and BikeNazi reader/correspondent Bob T, and got myself a high-visibility safety vest.
I chose the Dickies model, in hi-viz green with red & reflective stripes. It's a little more expensive than many of the offerings online (there are bunches!), but it's ANSI compliant (Class 1) as Bob recommended, and the reflective stripes are 3M Scotchlite, rather than some Chinese knockoff. And, I purchased it from a local merchant. Maybe it'll keep me alive one more day... and perhaps D&B will stay in business one more day.
I wore it out of the store. Obviously it's not a silver bullet or a Force Field, but if it causes just one distracted driver to notice me who otherwise wouldn't have, surely it's worth the $ as well as any slight inconvenience or discomfort. (It's poly mesh, and if it prevented some cooling power, I didn't notice.)
Ironically, as I rode away from the store on Glenwood (a busy 5-lane arterial), I observed a new twist on against-traffic riding.
A kid who looked to be high school age came riding up the street toward me, and against traffic. Not so uncommon. But... this kid was sitting backwards on his 20-inch sting-ray style bike, riding looking over his shoulder, and with a big ol' Alfred E. Neumann grin on his silly face! So was he really riding against traffic? It might take a judge (or St. Peter) to sort THAT one out!