Any modification is possible if you point the money cannon at the vehicle and squeeze the trigger.
I would ask, though, other than the 'cool' factor, what is the objective? The advantage of a slide-in like a 4 wheel or a pop-up tent shell like a Wildernest or a Flip-Pac is that they don't require a dedicated vehicle - slide the camper out or take the topper off and you are back to having a pickup.
The dedicated camper-vehicle is great as a camper but pretty crappy for anything else. Also, even with 4wd, you aren't going to go very far off-road in a vehicle that narrow and top-heavy.
To put it a different way, that weight and height of that camper is going to impose limits on your travels that 4wd and low range can't remove.
I guess if you live in the snowbelt and want a year-round camper, it could be a good thing, but there's a reason you don't see a lot of 4wd motor homes - no matter how many times the concept has been tried (and it has, many times), there really isn't that much of a demand for them because a 4wd motor home can't go that many places that a 2wd motor home of equal size and configuration can't go.
Seems to me if you really need the comforts of a motor home and the capability of 4wd,something like a Sportsmobile 4x4 van would get you further into the back country with fewer compromises (think, for a minute, about the point where the fiberglass body of the camper and the metal body of the truck come together, and then imagine the body flexing and twisting on a rough 4wd road. You can see the problems that would be very likely to occurr.)