I did a similar project not long ago. The hot water recirc. pump I found came in 2 models- one which is installed under the sink and requires an electrical outlet under the sink, the other is installed at the water heater, both use a thermostatically controlled valve (when temp drops, it opens the valve and recirculates the water). It was very easy to do, and doesn't require a return line to be run. It uses the cold water side as the return instead of running new pipes. Check out the products "autocirc1" and "autocirc2" @
http://www.autocirc.com.
I'm no professional, but I hope this may help you out!