Tigers (
http://www.tigervehicles.com/) come with all sorts of 4WD options. You can order regular, extended, or crew cabs. There are several models and lengths of Tigers.
My Tiger has 4WD with a limited-slip differential. I am happy with that. Most of my 4WD travel is what you might call "4WD lite" - smallish rocks, sand, gravel, maybe a bit of mud. You are not going to be able to rock-crawl or do Jeep sorts of things with any vehicle as large as you are talking about unless maybe you get something with a Fuso chassis.
