Europe’s largest car show has long been a source for fantastic debuts. This year marked a trend reversal for many carmakers, as small-car companies like Mini and Peugeot introduced more comfortable models, while large-car makers scaled things down. Several breathtaking designs were also on display, like Lamborghini’s futuristic $1.4-million carbon-fiber Reventon. But the mantra of the show was “fuel efficiency.” From hybrid-diesel engines, to ultracompacts, to plug-ins that could power a house in a brownout, Frankfurt’s carmakers had gas-sipping on the brain in 2007.

For a look at the newest and shiniest Europe has to offer, launch the slideshow here.

Mini Clubman: Stretched 3-Door

The Clubman was possibly the most highly anticipated debut at the show. This stretched Mini features a larger backseat and a bigger rear cargo area.

Ford Verve: Future Ford Compact

The Verve concept forecasts the company´s plans for an upcoming compact model. This is basically a styling exercise; technology innovation is limited to little touches like LED lighting.

Kia Kee: Four-Seat Coupe Concept

Kia is ready to announce its graduation from economy cars to luxury models. The Kee sport coupe features a 197-horsepower V-6 engine and six-speed manual transmission wrapped in a sleek “2+2” body (with tiny rear seats) courtesy of the company’s new German design center.

Mitsubishi Concept cX: Clean Diesel

The Concept-cX shows Mitsubishi’s notion of high performance in an environmentally conscious world. The cX is a turbocharged all-wheel-drive sporty compact SUV employing a dual-clutch transmission for maximum power to the road. But the engine is a fuel-efficient 1.8-liter clean diesel featuring a variable geometry turbocharger that maximizes turbo boost, plus a catalytic converter (new for diesel cars) and a particulate filter to minimize emissions.

Audi RS6 Avant: Twin-Turbo V-10 Wagon

When the baby is crying and you need those diapers fast, Audi has your car. To build the RS6, the company stuffed a 580-horsepower twin-turbo V-10 engine into its A6 Avant wagon. The result: the speediest grocery-getter ever built.

Jaguar XF: Facing the Future

The XF marks Jaguar’s first serious effort to remake itself as a contemporary manufacturer competing on the merit of its products rather than trading on nostalgia. The supercharged 4.2-liter V-8 cat will compete against sleek sedans like the Mercedes CLS-Class.

BMW X6 Concept ActiveHybrid: Hybrid Crossover Coupe

BMW’s latest concept is a new kind of car: the sport activity coupe. It’s basically a four-door sedan with a sloping coupe-like roofline and a jacked-up four-wheel-drive undercarriage. The concept also features a version of the fuel-saving two-mode hybrid-electric transmission that BMW has jointly developed with General Motors and DaimlerChrysler.

Nissan Mixim: Scissor-Door Three-Seater Concept

Nissan is targeting this all-wheel-drive electric subcompact at younger buyers more accustomed to PlayStation than to Plymouth. The Mixim puts the driver in the center of the car, with two full-size rear seats and a little child’s seat/parcel shelf behind the driver. Passengers enter through large scissor-style doors that lift out of the way.

Volvo ReCharge Concept: Plug-in Hybrid

Volvo exhibited a plug-in hybrid electric concept that uses wheel-mounted electric motors for propulsion. Juice comes from lithium-ion batteries than can be charged by a wall socket or by the on-board flex-fuel 1.6-liter internal combustion engine. Able to run 60 miles on batteries alone, it gets a long-range fuel efficiency of 124 miles per gallon. And the car can literally power a house if the electric grid goes down.

Opel Flexstreme Concept: Stows Segway

As more cities consider fees for driving into congested areas, models like the Opel Flexstreme make a lot of sense. This concept car is designed to carry a pair of folding Segway scooters that can take the driver and a passenger from the car’s remote parking place straight to the office. The car itself is a plug-in hybrid electric diesel.

VW Up! Concept: Rear-Engine Microcar

After years of identity crises, VW has remembered that it was a small, affordable, rear-engine vehicle that made the company’s name. The Up! brings Volkswagen back to its roots, with a tiny, cheap-to-manufacture car. The company is already plotting variants such as a mini-bus.

Peugeot 308 RC Concept: French Sport Coupe

Small cars are efficient, affordable and practical–but not exciting. So as Peugeot launches its new 308 subcompact in Europe this fall, it’s trying to stoke interest by also showing a concept sport coupe based on the same platform. The backseat is of questionable utility, but the company claims the trunk will hold a mountain bike.

Lamborghini Reventon: Million-dollar Supercar

If you had a spare million-plus dollars and were already a favorite Lamborghini customer, you might have made the list of 20 buyers for the Reventon, a flat-black car resembling a cross between a stealth fighter and the Batmobile. It’s essentially the 640-horsepower, $356,600 Murcielago model with a lightweight carbon-fiber body.

Porsche 911 GT2: Turbo Track Weapon

A Porsche press announcement calls this car “the fastest and most powerful 911 homologated for the road ever to see the light of day.” Translation: 530-horsepower driving through all four wheels.

Mercedes-Benz C63 AMG: Compact V-8 Thunder

It is obligatory for manufacturers of sport sedans to challenge the BMW M3. And this time, Mercedes has a shot at succeeding. The C63 AMG is armed with 457 horsepower and a thumping 442 pound-feet of torque, along with taut handling and a smart seven-speed transmission that may help it beat the Beamer’s lap times.

BMW 1-Series: Compact Fun

BMW returns to its roots with a light, compact sport sedan for a new generation of customers who don’t desire the company’s big, thirsty, gadget-laden models. Engine options include a pair of diesels and a 304-horsepower gasoline twin-turbo inline-six for world markets. In the U.S., we will get the twin-turbo 135i and a less-powerful 128i gas engine.

Mercedes F700 Concept: Efficient Luxury

The F700 offers a preview of the future of large luxury sedans. A 238-horsepower twin-turbo 1.8-liter four-cylinder engine and 20-horsepower electric motor will propel the car to 60 mph in 7.5 seconds, while squeezing out 44 miles per gallon. A forward laser scans the road ahead so the F700 can adjust its active suspension for conditions to come.

Fiat 500: Minicar Depicted as Children’s Ride

Fiat’s tiny 500 has long held a warm place in the hearts of European drivers. The company hopes to capitalize on that goodwill with a new 500 subcompact that promises outstanding fuel economy from 1.2- and 1.4-liter engines and five-star safety ratings, thanks to seven standard airbags.

Suzuki Concept Kizashi: Full-Size Sport Sedan

While the rest of the industry rushes toward the kind of small cars Suzuki’s famous for, the automaker tries to bust out of its stereotype with a massive sport wagon that looks like a hot-rodded Dodge Magnum.

Toyota IQ Concept: The Minicar Future

The challenge of urban parking drove Toyota’s design for the IQ concept car, which is less than 10 feet in length. Helping achieve that small size is a 3+1 seating arrangement: The seat directly behind the driver is for short-term riders or small children, while the other three are designed for adults.