At first glance, I thought that must surely be a double-bunk sleeper; then, I take a closer look and it is obvious why it stands so tall.
Notice how much lower the van's rocker-panels are, compared to the bottom of the sleeper.
To properly mount a road-tractor sleeper behind a light-truck, one must "saddle" the bottom of the sleeper, thus bringing the top edge of the opening level with the top edge of the back-glass cut-out of the ton-sized truck.
I have the second genuine sleeper on my F-350; the first was off a Freightliner and is Freightliner issue; the second/current one is a lot more deluxe and is a genuine Double Eagle.
Both these sleepers have been drastically modified to mate with the much lower cab-opening of the smaller truck.
That sleeper is just as it came off the big truck.
I bet that whoever mounted it had to plate/seal over the normal opening and cut the bottom of the opening deeper to get things to line up.
Were that sleeper properly altered and remounted, it would look a lot better.
