Well your primary reason for that is most people are not going to spend the money on it. People that come into pet shops usually have one or 2 reptiles and selling them flexwatt heating like what you would need for you rack is not going to happen and flexwatt in the hands of alot of people is dangerous....As far as real thermostats, again it sounds bad, but most people care little enough about the reptiles as pets you tell them they need a $50+ thermostat and they are not going to buy. I used to build dimmer switches wired into extension cords and sell them at the pet store