How much force is created (i.e. if the jeep were to land on someone during the rollover) when a 4000lb jeep rolls down a hill with a 60 degree incline?

The Jeep rolls from a very slow speed. Video below:
http://www.youtube.com/watch?v=wyIDNn73H4U

The jeep didn't roll over anyone in this accident. But if it had rolled over someone the force that person would experience depends on how much of the vehicle's weight lands on the person versus how much is carried directly by the ground. In the worst case it would be the full weight of the jeep, which is 4000 pounds. This is a lot less force than if the vehicle smashes into something solid, like a rock. In that case the forward momentum of the vehicle comes to a halt in a very short amount of time. From impulse and momentum principles you have


F \Delta t= m \Delta v

If the 4000 pound vehicle is doing about 20 MPH and comes to stop with 2 feet of crumbling of the front end it equates to about 26000 pounds of force.