General Motors’ message in Detroit is centered on two themes: Get younger and greener. On display is the rugged Hummer HX Concept that is designed to attract younger buyers, and the Saab 9-4X BioPower Concept.

Three young designers who were new to GM designed the HX Concept as a smaller and more youthful Hummer. The 304-horsepower 3.6-liter V6 engine is mated to a 6-speed automatic transmission and is E85 capable.

With unmistakable Hummer design characteristics, the two-door vehicle has a convertible body that can be adapted to off-road conditions. Two removable roof panels allow for an open-air driving experience and the modular rear roof assembly can be removed as well.

Different rear roof assemblies allow the HX Concept to be configured as a sport-utility truck (SUT) with the roof assembly removed, a slant-back or a traditional SUV design with a larger covered cargo area.

The HX Concept on display was configured as a slant-back design with the removable fender flares and doors in place. The doors can be quickly removed by pulling pins in the exposed hinges, and the composite fenders are attached with quarter-turn quick-release fasteners to allow easy removal for narrow trails or rock climbing.

CEO of General Motors Rick Wagoner also announced a partnership with Coskata to produce ethanol by using a new process that is not dependent on corn and requires much less water than other processes. A pilot program is expected to be in place by 2009 with the cost of production at less than $1 per gallon.

The Saab 9-4X BioPower Concept is confirmation of Saab’s plan to enter the crossover market. Optimized to run on bioethanol (E85) fuel, the concept is powered by a 2.0-liter four-cylinder turbocharged engine that combines the advantages of turbocharging, direct injection and variable valve timing with high-octane E85 fuel. The 9-4X BioPower Concept also features Saab’s XWD all-wheel-drive system with active torque management.