the mid 90's taurus fans (3.8L) are some very heavy duty suckers they are some serious power pullers as well. The benefit is that they are a 2 speed fan. The high speed pulls when running better than 20 amps I belive it is actually rated to pull almost 30 amps and I know that they move some air. Even though the radiator on a taurus, when the high speed kicks in you can actually feel the air being pulled through the grill. I happen to have one sitting around that I was going to use in a dedicated wheeler. There is physical space to fit 2 fans on the inside of our radiator since it is so tall I just haven't figured out the exact mounting. I have plans eventually to try and see what I can make work just have to take care of some safety precautions first. 1. Real Temperature Guage, 2. Upgrade alternator ( Taurus stock is 130 amp)
I can say that the taurus fans are what most of the offroading community swears by for an inexpensive but very reliable fan. Keep in mind that these are in trucks that when put to use will see 5mph tops but will run 3-4000rpm out of small block V8's for hours on end and with one of the major wheeling spots being moab utah in the middle of the desert I can't say that anyone I know of running on has had any major overheating issues other than those who didn't supply the motor with enough power and burned up relays or switches.
I think it is possible in any climate in north america towing heavy loads to run with just an electric fan(s) Though before attempting such I would definatley want to be running a real temperature guage not the POS in our dashes. because I can tell you that by the time I get to "M" or "A" I'm going to be worried and by the time it made it over to the red area I'm sure I'd have an overheated motor.
The key to any cooling system is shrouds if you take a look at any pulling fan you will notice a fan shroud around the fan that prevents it from pulling air from behind the fan. This is an absoloute requirement especially on vehicles with static resistance through the a/c, and radiator, and even possibly an intercooler. They provide enough resistance that it's easier to pull the air from back behind the fan around instead of the cool air infront of the stack. If you have a good shroud you prevent this. Another step that you will find in many applications is some sort of foam insulation or rubber stripping between each component in the stack this ensures that the air flows though instead of around each component instead of only through the one closest to the fan.