I seem to remember an episode on Ask This Old House about an under counter water pre-heater. If I remember correctly, this was installed to eliminate the few minutes of cold water that comes out of the hot water side when it is first turned on. I think the solution was an under counter heater that acted like an instant hot water heater but was thermostatically controlled to shut off when hot water from the tank reached the faucet.
I was searching the web for something like this but all I am finding are circulators.. Am I remembering an episode correctly or should I look at taking a vacation?
Thanks for the info!!!!!!