Yes, three-wheelers are back. And the world has Canada to blame. There are no fewer than five unique Canadian three-wheelers in various stages of completion -- from prototype to road-going. Let's see what's been in our syrup.

First, let me introduce the coolest automotive manufacturer in North America: Westward Industries, from Manitoba. They produce the Go-4, primarily for parking enforcement, mail deliveries, and, uh, security patrols. They are all over the U.S., but unfortunately only street legal in Manitoba. Good work, bureaucrats. Although the Go-4 is limited to 64 km/h (40 mph), it's has a better power-to-weight ratio than the Smart Fortwo.

Uncorked, it'd make you the fastest parking enforcement officier in the Big Apple.

Next up is Campagna. In 1994, French entrepreneur Daniel Campagna decided to develop the T-Rex. It has two wheels for steering and a single rear wheel powered by a motorcycle engine. There's evidence Campagna knows what he's doing -- he once wrenched for Gilles Villeneuve.

The T-Rex hasn't been changed much since -- just steady updates to utilize the latest in engine and suspension technology. There's also a convertible version, the T/A ... if you feel that a vehicle that can pull 1.9 g of lateral acceleration with no doors also needs no roof.

Across the country in Mission, B.C., upstart maker FuelVapor Technologies has developed a prototype vehicle, called al, that will pull 1.7 g on a skidpad, hit 100 km/h in five seconds, and can drive for 15 hours without filling up. That's Vancouver to San Francisco on one 37.8-litre (10 gallon) tank.

To achieve these impressive claims, developer George Parker has mated a very light three-wheeler body (25 percent less drag than a four-wheeled vehicle) with a 180-hp turbocharged VTEC Honda engine. His company plans to enter the automotive X-Prize competition this year. But the company needs investors to start production.

For the more extreme-minded, we have the Bombardier Can-Am Spyder -- which is probably exactly what a baby T-Rex would look like. Also motorcycle-powered, the Spyder places the driver in a more bike-like position. The devices will be hitting motorcycle dealers soon, at an asking price of $18,500.

Finally, late last year, Harley-Davidson announced a partnership with Lehman Trikes, Inc. -- originally from and still making trikes in Westlock, Alta. The Lehman-made trikes will be sold by Harley as official Harley models.

Around the globe there's Carver Europe, which makes the Carver One -- a three-wheeler with two rear wheels that tilts into a corner. Aside from supposedly being initially an incredibly traumatic experience, it combines the best two parts of a car and a motorcycle: weather protection and leaning, respectively. It has a five-speed manual transmission mated to a 65-hp, 660-cc turbocharged four-cylinder engine -- perfect for a fuel-sipping commute.

At the 2006 Los Angeles Auto Show, Volkswagen -- of all companies -- showed the GX3, a concept very similar to the T-Rex. Powered by a 1.6-litre turbocharged four-cylinder engine, it promised a 0-100 km/h time below six seconds and VW said the car was "extremely likely," for production. What happened? Some internal research concluded that it couldn't be made for its target $17,000 (US) asking price, and it would subject the company to an onslaught of product-liability lawsuits.

As for bikes, there's the Piaggio MP3 -- not a digital jukebox but a three-wheeled scooter with two wheels up front. It features an interesting front suspension that is basically two scooter suspensions attached with a metal parallelogram, with a central steering arm. The whole enchilada can be locked at low speeds -- else the MP3 will list like the Exxon Valdez. Advantages over a conventional scooter are that it can be parked like a car without a kick stand, better stopping distances, and better stability. It's available in Canada, too.

But let's get serious: even the Brits, eternal tinkerers as they are, took their tweed hats and ran far away from the concept of a road-worthy tripod.

Nevertheless, some companies still believe -- and have proven -- that three-wheelers are particularly suited to certain tasks. Let's just hope we keep drinking the three-wheel syrup.