Your friend with the MB BluTec diesel has a nice tow vehicle for sure. What I think needs to happen is to properly match the TT to the TV. The limiting factor on these small Diesel SUV's IIRC is the receive rating.
The Tiguan is a very nice SUV and would handle a small pop up or Chalet type folding camper (a very small one at that). Mostly because the receivers are only rated for 350 lbs of tongue weight and is NOT rated for a Weight Distributing hitch at all. This is not a good tow vehicle for towing a hard sided TV at all.
I won't address the Diesel vs Gas statement very much...I lean gas because you can get a MUCH higher HP, lower purchase price, lower maintenance cost, and lower repair cost...
As far as vehicles to tow with...there are many that would absolutely fit the bill with some careful consideration for the trailer weight and the tongue weight.
1) Ford Expedition with the Max Trailering package
2) Dodge Durango with a Hemi V8
3) Jeep Grand Cherokee with Hemi or Eco Diesel
4) GM Tahoe/Yukon/Suburban etc
5) Toyota Sequoia
6) Nissan Armada
If you can stomach a crew cab truck you can get some very very nice options such as the
Chevy Silverado with the NHT Trailering package and a 6.2 V8 (over 400 hp)
Ford Max Tow F150 with EcoBoost
Ram 1500 with 3.92 rear end and 5.7 Hemi
Tundra 5.7 with tow package
Remember, you are going to be using a Weight Distribution hitch with a travel trailer. I highly recommend getting a power tongue jack to help ease the hitching process. I know for me...hitching up went from a work out to a piece of cake once I got a power tongue jack.
Good luck and let us know how this works out for you.
Thanks!
Jeremiah