I never had one of those bikes with the pedal-shifting mechanism, nor did I ever have any friends who had one. However, I remember an ad in Boy's Life Magazine back in the 60's (when I was a kid) that promoted the device.
If my memory serves me correctly, the transmission was made by Bendix. The ad was a multi-panel cartoon style with a kid calling a piano tuner because there were so many cables on his bike for shifting gears and braking. The piano tuner wisely recommended the new Bendix rear hub that could change gears and provide reverse pedal braking. I guess the ad made an impression on me because I still remember it.
Bill Silverman
Pasadena, CA, USA