Photos: Tomorrow's cars rally in Tokyo

For photos from last month's auto show in Frankfurt, Germany, click here.

Among the automakers showing off fuel cell vehicles at the Tokyo show is DaimlerChrysler, whose protoype line includes the sleek Mercedes F 600 Hygenius concept car. The Hygenius' high-voltage battery and hydrogen tank are located beneath the passenger cell, and its electric motor has been built into the rear-axle carrier.

Fuel economy isn't the only thing on the mind of car designers. Honda's six-passenger WOW concept wagon has a wooden floor and also functions as a kennel on wheels.

Seats in the middle of the WOW can be reconfigured into a dog carrier.

For dog lovers who want to keep a closer eye on Fido, the glovebox also packs a pooch. Take a bow, WOW.

The Pivo, from Nissan, is an electric car with a bubble-shaped cabin that rotates 360 degrees. If you get stuck in a tight spot, just spin the cabin and head back the way you came.

The interior of the Pivo keeps things simple. And very, very red.

Toyota has a different take on turning on a dime--its Fine-X has four independently steered wheels that enable it to rotate on the spot. Powered by a fuel cell hybrid system, it also has gull wing side doors that open upward.

The I-swing from Toyota is a one-seater running on three wheels--and two when in slow mode. "In addition to the stick control, a pedal control can be used to provide a fresh cornering feeling, as you shift your body weight as if you were on skis," Toyota says.

Mazda's Premacy Hydrogen RE Hybrid is a minivan concept whose power unit combines a dual-fuel, hydrogen/gasoline rotary engine and an electric motor.

The dual-fuel system in this RX-8 from Mazda enables a driver to select gasoline or hydrogen by simply flipping a switch. The Japanese carmaker plans to make this vehicle available for lease soon.