Unfortunately, my new Sigma BC 1009 STS wireless bike computer doesn't have that ... but the installation guide teased me that the next higher model, the wireless BC 1609 STS Cadence, does. So yesterday had another trip up the street to Bothell Ski & Bike, where I asked about a trade up. They couldn't do that per se (I was missing the packaging), but they gave me a very reasonable deal on the BC 1609.
Newly equipped, we rode out for local errands today. Between the cadence metric and the one additional day's experience, I was far smoother, and enjoyed it more as well.
Even a minor crash at the end didn't ruin my mood. I lost my momentum on the last rise before the house (as Katherine describes it, a very "short but nasty hill"), and my wobbling recovery was interrupted by a looming curb. Too much was happening, and I tipped over. I at least used my limited aikido head knowledge, and I let my fall morph into a sideways roll rather than being stupid and trying to straight arm the sidewalk on the far side of the aforementioned curb. The result was only minor damage: I noticed my shoulder for a few minutes, the handlebar needed to be twisted straight, and Katherine pointed out that I had a classic road rash on the outside of my leg.
(I did straight arm a sidewalk once, on ice around New Years 1984. I remember it well, not to mention the resulting dislocated left elbow that would ache off and on for the next fifteen years. I'll risk the unpracticed amateur roll, thank you.)
I'm not ready to match the summer of 1985, when at ~ 150 pounds I rode over 1300 miles, but small progress is being made.