Moab is a small town surrounded by stunning scenic views and dirt roads that trail off into the Utah badlands. Many of the trails lead to abandoned uranium mines, worked in the Cold War years as a strategic resource. These days, the trails around Moab are a national treasure of a different kind. These days, Moab is a Mecca for four-wheeling.

The week before Easter, off-road enthusiasts from all over the world fill the town's motels, restaurants, and car washes and keep the tire stores, auto parts shops, and four-wheel-drive shops open until midnight. There are roughly 30 different trails that are marked, rated, and maintained by the Red Rock Four Wheelers, who deserve credit for bringing business to the town of Moab and preserving the quality of the experience for all.

Over the years, manufacturers including Jeep, Hummer, Toyota, Volkswagen, and Land Rover have used Moab trails to prove and launch their new four-wheel-drive trucks and SUVs. Perhaps most conspicuous among them is a group of Chrysler employees that calls itself the Mopar Underground.

This is a group of engineers and designers, headed by chief designer Mark Allen, that has been customizing production vehicles since 2002. Instead of using static auto shows to display their creations, the team brings the vehicles to Moab for the annual Easter Jeep Safari and takes to the trails, allowing enthusiasts to see, touch, and sometimes even drive their latest custom 4x4 concepts.

"Moab works as a proving ground to test Jeep vehicle concepts with Jeep enthusiasts," Allen says. "We use knowledge gained at this event to explore new directions and develop Mopar Performance parts to suit these vehicles."

This year, the Mopar Underground team brought a brace of previously unseen modified production vehicles. Officially, these are considered concept vehicles...but each working prototype explored an idea that may very well make its way to the marketplace in the next 12 months. Here are some of the highlights: