Here's a custom "jeep" that I found on the DieselPower.com web site. I say Jeep in quotes because it's really a Dodge truck with Jeep-like bodywork.
The vehicle was constructed by 4 Wheel Offroad Magazine as part of their "Ultimate Adventure" off-road competition. The truck is called the Ultimate Adventure 2007 Jeep Wrangler JK. But since it has Dodge Power Wagon running gear, it's referred to as the Rubi Wagon.
The build starts with a 2006 Dodge Ram truck chassis. The frame was shortened. AEV installed a 5.9L Cummins diesel, which is set back 12 inches to allow AEV's Jeep hood to cover the engine and the extra large radiator needed to keep things cool.
The Jeep body came from a 2007 JK Unlimited. AEV did the cutting and fitting to get the Jeep body onto the Dodge frame. The Jeep JK firewall and floorboard had to be modified quite a bit to fit around the engine. AEV figured out how to make the diesel work with a Jeep wiring harness.
Transmission is a Chrysler NV4500 5 speed. Transfer case is an Advance Adapters Atlas two speed model.
AAM axles from a Power Wagon were added. They're fitted with 4.56 gears and electric selectable lockers front and rear. The low gearing was required by 42 inch BF Goodrich Mud Terrain KM2 tires, mounted on 20 inch Poison Spyder beadlocks. Superlift provided a custom suspension with hydraulic ram assisted steering.
In testing, the stock front axle proved to be a weak point. The Cummins provides a lot more torque than the stock Power Wagon Hemi.
The build is described here
More photos of the vehicle build on the 4wheeloffroad web site