I think when heating a room to that temperature, you should better NOT forget a thermostat
Something should still control whatever is getting the temp up there, or in a small room the temp can quickly rise far beyond that.
And as Redshepherd has said, the cost for running a space heater to keep up that temp can quickly add up depending where one lives. And its not without risk, either. But then again, neither is heat tape or any other method of heating.
I still think for only a few snakes, it is far more economic to heat the rack rather then the room.