I use a ford with the 5.4. I tow my Jeep with no problems at all. It will tow at 75-85 mph. It gets about 12 - 14 mpg when towing at a normal speed.Wife uses it as a daily driver and gets around 16mpg, and it's a 4x4 F250.
IMO you dont want anything smaller than something in the 5.4 class.