It depends upon how many miles and on what kind of roads you plan to tow. Your Toyota has a truck frame but the SUV's you mentioned have a car unibody design that is lighter but not nearly as strong for towing.
Be sure to consider the weight of the SUV with passengers and the weight of the trailer when fully loaded (take dry weight and add 500 kilos).
The VW Toureg has a well deserved reputation as a very unreliable vehicle and would not be something I would ever consider for a tow vehicle. Nothing worse than having a breakdown on the highway while towing anything. The Mercedes SUV's have a similarly bad reputation for reliability though their quality has improved the past couple years and they now rank above the BMW X5 vehicles (which rank above the VW.
The other problem is that for prolonged towing I would not trust the cooling system for the engine or the transmission to be 100% effective. Not a problem if you only tow the trailer a couple weeks out of the year but a concern if you use the trailer a lot.
Vehicles designed for towing will have the option of a tow package which will include wiring for the trailer and its brake controller and additional cooling capacity for the engine and the transmission.
I would take a 4Runner over any of the cars mentioned. There is a reason why Toyota trucks have for the past 5 years been at the top of the list for reliability as ranked by JD Powers. The 4Runner is also rated much higher in durability than Mercedes/BMW/VW. Chrysler is not noted for the reliability of its vehicles and its SUV's are rated even below the VW Toureg. The ride of the Jeep's is going to be the worst of any SUV if that matters to you.
SUV's have their place but there is more utility in having a 1/2 ton pickup with a crew cab instead. Lots more room in the bed of the truck for bicycles and pets and gear and supplies and with a shell you can more easily carry a boat or skis or other recreational items. Resale will be better as well.