I was recently in the Philippines and I saw a Ford Everest's. It's based on the Mazda-based Ranger for the asian market. Like an Explorer but maybe a little bigger, but not as big as an Expedition. They've got decals on the side, proudly proclaiming a turboed and intercooled diesel. I guess they're 2.7L or something.
Probably wouldn't be suitable for the US market (or us in the US). A motor that small in something that big would be considered way underpowered. I rode in my uncle's late 90s Mitsubishi Pajero (same as the old Montero) and that had a 2.8 turbo intercooled diesel through an automatic. On the freeway I could tell the RPMs were pretty high, which to me indicates that they make up for the lack of horsepower in the gearing.
So yeah. If you're gonna do it, use a substantial motor that's gonna do at least what the 4.0L OHV does