A high flow thermostat? You can get thermostats that will open at different temperatures, but a high flow thermostat would have the same problem as no thermostat. You might mean one thats rated at a different temperature.
Look at the size of the hole in the thermostat housing, and then examine a thermostat. You will see that the body of the thermostat takes a substantial amount of the hole, and the hole in the actual thermostat is considerably smaller. This provides a restriction in the system to slow the flow of water. If you have a monster radiator, then you may get away with enlarging this restrictor, but with a normal radiator you do not want to increase the water flow. Of course, you dont want to slow it down much either.
If you live in a tropical area, you already know about this. Its common up north to run a car without a thermostat, but the thermostat is not actually removed. It tends to happen in places like Darwin, if a thermostat craps itself on a journey and you need to get the car going.
You can remove the thermostat, cut the bars that hold the springloaded valve in place, and stick just the body of it back in without the valve. In this way, the body of the thermostat provides enough restriction to slow the water flow, but the thermostat is no longer stuck open or closed because the valve is removed.
Since you dont really need a thermostat in a town that rarely ever gets colder than 15 degrees, people would leave them like that for months or years without getting around to putting a new one in.
People with less experience though would remove the thermostat altogether, and discover their cars running temperature rising significantly, often to the point of engine damage.
