The battle between heart and head continues at the North American International Auto Show today.

Both General Motors and Toyota revealed vehicles that appeal to consumers’ love affair with horsepower and hauling cargo as well as vehicles that appeal to those with an environmental bent.

GM unveiled the latest iterations of its Cadillac brand, with Jim Taylor, Cadillac brand manager, and Bob Lutz, vice-chairman product development, talking up the 2009 Provoq concept, a sporty Cadillac crossover that is powered by an onboard hydrogen fuel cell. It also has lithium ion batteries designed to give the vehicle some extra power should it be needed. It will emit nothing but water vapour.

Lutz compared the Provoq’s debut to that of Apple’s iPhone. It, like the iPhone, has the potential to shape how consumers view crossover luxury vehicles, he said. “It’s our vision of the future of luxury transportation,” he told the assembled media. “It marks the next great paradigm shift in the auto industry.”

Although Cadillac has had its low points, the brand remains an important one for GM. It has long been associated with status and success, and GM is pushing the brand in growth markets like China and Asia. China is now the third biggest market for Cadillac. It is also indicative, said Lutz, of GM’s focus on technology and design.

Of course, most automakers can only contain themselves for so long before they start talking about horsepower. Moving “from green to mean,” and accompanied by a gospel-style choir and live band, Lutz debuted the 2009 Cadillac CTS-V, a limited edition high-performance sedan that aims to be the fastest production sedan in the world. “We looked at the best of German performance cars and tried to outdo them all,” said Lutz. A V8 engine that can produce 550 horsepower powers the CTS-V. Not quite Corvette territory, but close.

Ed Welburn, VP of global design for GM, also showed off the Cadillac CTS coupe concept. If produced, it’s intended to be powered by a range of powertrains, including diesel.

Meanwhile, Toyota took the wraps off the luxury “crossover sedan” the Venza today. It rolled through the Riverview ballroom at Cobo Center and onto the stage to applause from many of the assembled media. Bob Carter, Toyota division group vice-president and general manager, said the automaker hopes to “launch a new segment, not just enter one.” The 2009 Venza will be built at Toyota’s Kentucky plant and is designed to appeal to boomers and empty nesters who don’t want to be limited by a sedan. The Venza has exterior SUV styling but has a low roofline which gives it the look of a sedan or a slightly overgrown station wagon.

Toyota already has the RAV 4 small SUV in its lineup, but Irv Miller, Toyota’s VP of corporate communications, said an aggressive marketing plan will ensure potential consumers will know the difference between the two vehicles. He dismissed the notion that Toyota risks cannibalizing the RAV4 for the Venza arguing that each vehicle has a distinct target market.

The Venza was first shown off as the FTSX concept three years ago.

On Sunday night Toyota also announced an ambitious environmental agenda for the next few years. Katsuaki Watanabe, president of Toyota Motor Corp., said a diesel V8 engine will be offered in both the Sequoia SUV and the Tundra pickup, in the “near future.” By 2010, Toyota plans to accelerate its global plug-in hybrid program, delivering a fleet of plug-in hybrid vehicles that will be powered by lithium-ion batteries. Two new hybrids are planned for next year—one for Lexus and one for Toyota.

Also today, Mini announced the Mini Clubman, a long wagon-like variant of the Mini which will go on sale in the U.S. next month. Mini also plans to expand its U.S. dealer network to 95 by 2010 from the current 82.