Cummins has announced it will supply 4.2-liter V6 and 5.6-liter clean diesel engines to DaimlerChrysler for light-duty vehicles. We can get an early look at the potential of such deal at SEMA next week when Jeep shows off a custom Wrangler Unlimited from the Mopar Skunkwerkes group. This teaser email I received says it's powered by a 4.2-liter diesel. Code named 50 JK, the hardtop Jeep features custom bumpers, 4-inch lift, 35-inch tires, carbon-fiber hood, Dana 44 axles front and rear, GPS and full saddle leather. This one's sure to be "Trail Rated." All totaled, Chrysler will have 65 vehicles on display at SEMA. Wonder how many will be boasting fuel efficiency?