It is very interesting that everything has been replaced except for your radiator fan and the relay that controls the fan unit.
A mechanics shop should be able to tell you if your fan is working by using a 6 volt latern battery and some speaker cable.
If the fan works then it is your relay that controls the fan that might have died. Link below
I replaced both in my jeep and overheating disappeared. Bought the repalcement fan from Ebay and fan relay from Oreilly's.
Wants to overheat and go into the "red zone" but as long as I keep the heater on high/defrost and go above 35 mph, it seems to stay just past the line before the red zone. If I'm going slow then it creeps towards the red-zone but as soon as I'm going fast again it seems to cool off.
I've had the transmission flushed, the radiator flushed, put in new thermostat & gasket, new water pump, upper & lower radiator hoses, temperature sensor gauge and fan clutch.
No water in the oil or smoke out of tailpipe. Could it be a cracked head or ...?