I took the easy route, knowing there was a low probability of success. I ordered a T9 LED light what would be an almost drop in replacement for the tube and "electronic ballast" (aka switch mode power supply) in my now-disassembled bench lamp. It arrived tonight and, indeed, it would be an easy replacement. It even came with clips to hold the light in the fixture.
This is what I was talking about before. No matter WHAT LED light source you use, you WILL have to build your own nice, quiet, resistor-ballast linear power supply for it. There pretty much is NO SUCH THING as a "quiet" LED power supply; the entire industry, and all the specialty silicon that has evolved around it, is based on modular CC buck converters using PWM regulation. Don't send it back; gut it and do the job you know you need to do anyways.
mnem
"Don't turn it on; take it apart!"
* worsthorse hangs his head in shame
I know, I know. I was being hopeful and lazy (note the statement in my original post,
I took the easy route, knowing there was a low probability of success). If it worked, problem solved, and on to something more interesting. Plus
amazon returns. The light I bought is glued together; getting to the supply will destroy the case, which is the reason I decided to try it. So now to order something with a supply I can easily remove or to build something from scratch.
edit: that said, the sheer
level of RF noise this particular LED supply put out was quite impressive. i've seen noisy LED supplies but nothing quite like this. it was worth trying it out just to see how bad it could get.