Thanks for the reply T18skyguy. The on-demand unit we have in our house actually came with a wired temperature control remote that can be mounted in a convenient location. I was going to install it near the kitchen sink, but so far we've seemed to settle on the 122* setting for most uses.
You brought up another good point about trickling water to wash dishes. The system needs a minimum flow to fire the burner, so if the hot water is trickling, the burner won't fire and the water turns cold. I suspect this is what also happens in RVs with the shut-offs on the shower head which allow a trickle. The on-demand heater shuts off and starts filling the hot water line with cold water. When the valve opens up, the person in the shower gets the dose of cold water before the hot water starts flowing again.
Thanks again,
~Rick