How do I install a tempature regulater that releases only hot water to the shower. Im wasting water!

My home is on a concrete slab and I find my self waiting 5-7 minutes every morning for the water in my shower to become warm. I am trying to find a product that will not release water flow until the water tempature reaches the 95 degree range. I did however find a product that with automatically stop the water flow when it reaches 95 degrees. I would still be waisting a large amount of water though. Are there any tempature regulators that would be mounted to the actual shower head or to the copper lines just inside the wall?

There are two approaches to that problem. A recirculation system that returns the cold water back to the tank until it turns warm and a hot water on-demand system that heats the water near the faucet. The downside to the recirculation system is that it requires installing a third pipe back to the tank to return the water. The downside to the on-demand system is a heater must be located near each faucet or shower to get the benefit at all of your faucets.