I work for a company that sells vehicles to NGO's and other aid organisations. Vehicles that get used much harder than Safari trucks. However, I happen to know that the is very popular. Looks about as boxy as an old Land Rover Defender. Very tough car. I sell the equivalent Nissan, the Patrol, which gets a lot of UN action, not so much safari.
Fun fact: the tail light on the Defender being built today hasn't changed since the late 50's, i think, when it graced the Morris 1000. Also, my dad has a 70's Defender, restored (well, it runs, but it ain't exactly mint...), and the cabin of the low-spec defenders they build today, are basically exactly the same...
Toyota LandCruiser 70 series