What's a fuel efficient SUV on the market?

I've been searching for a small-mid sized 4WD wagon with low range and a turbo-diesel engine. Fuel economy is very important, as this vehicle will regularly be doing very long trips, so less than 8L/100 km is desirable. But there doesn't appear to be anything on the market like this. I have looked at the T31 Nissan X-Trail, as it is the "perfect" size. A Jeep Renegade Trailhawk has some off-road capability, but it is quite small and "4-Low" is only 'simulated', it's not a true low range. The Suzuki Vitara and Great Wall X200 get a look in as well, but none of these except the Vitara has low range, and unfortunately the Vitara is a petrol guzzling V6. While the Renegade 'simulates' low range by locking in the lowest ratio in the auto gearbox, and the X-Trail doesn't come with the CVT in the diesel, (which could also 'simulate' a low range by locking in the lowest ratio of the CVT), but the diesel only comes with the standard 6-speed auto. The Suzuki Jimny/Sierra is just too small for two people and a weeks worth of camping gear. I need a vehicle that can have "muddy" tyres fitted, can climb quite steep ascents, and negotiate reasonable depth water crossings. Driver comfort, traction control, ABS, etc, and the ability to do 700-1000 km a day on the highway economically is also required. Is there any vehicle I have missed that you could suggest? I have been told over and over that I should buy a Patrol/Pajero/Prado/LandCruiser and stop trying to get a 'soft-roader' to go off-road." But I have a Pathfinder turbo-diesel already and really need something a bit smaller and more fuel efficient on long highway trips. A T31 turbo diesel X-Trail auto with a Low Range would be the ideal
car. Yeah, it has to be an auto because of other drivers who will share the vehicle, and to be honest; the new electronic autos are damn good.