The cables controlling the elevator in the Zero stretched, so that the response was roughly consistent throughout the plane's high speed range, which was at least new to Japanese craft. What were the other early examples of speed-adjusted controls?

You might have better luck posting in /r/aviation. There is also /r/AviationHistory but it doesn't have much traffic.

I'm also interested in the topic, and I have to wonder if the stretchy were by design, or just a byproduct of weight savings. From an engineering point of view I would expect the designers to be working hard to prevent flutter, and compliance in the cables sounds like a hazard.