If the world were a little different, there might be a Corvette four-door sedan.

Maybe even a Vette crossover!

I can almost hear Corvette purists muttering that those are two of the most ridiculous ideas they have ever heard.

"It would severely hurt the car's reputation if the Vette were stretched," they are probably whining. "Two extra doors, four seats, let alone talk about a dirt-grinding crossover! What's wrong with you?"

The thought of a four-door Corvette sedan occurred to me in the past several months as a tidal wave of Porsche Panamera spy shots and computer-enhanced images hit my e-mail directory. The Panamera is Porsche's sleek four-seat sedan that debuts in 2009. It will have a front-mounted engine and a coupe-styled body with four real doors.

The bottom line: a true four-seat, four-door Porsche sports sedan that likely handles as well as the cars that made Porsche an iconic brand. Porsche's strategy makes a lot of sense, as would a four-door, four-seat Vette sedan.

Porsche was criticized -- mostly by Porsche enthusiasts -- when word of the automaker's interest in an SUV surfaced in the mid-1990s. Of course, a new group of buyers embraced the brand once the Cayenne SUV hit the road. And a new group of buyers who found the previous Porsche coupes too small for their lifestyle or family needs now will have a realistic option, the Panamera.

I believe the same would be true for a four-door Vette sedan if it were developed.

ENLARGE With computer software technology, we created this exaggerated image of a four-door Corvette. In addition to adding the rear passenger compartment, we extended the trunk area and altered the styling of the rear window. The notion of expanding the Corvette line has occurred to General Motors' Bob Lutz, too. Photo credit: PHOTO ILLUSTRATION BY TERRY MICALLEF

Lutz is interested

Porsche isn't alone out there. Let's not forget about one of the stars of the 2006 Detroit auto show. The international and national press tossed truckloads of accolades at the four-door Aston Martin Rapide sedan, basically a stretched DB9. That beautiful car arrives next year.

Also, the four-door Maserati Quattroporte sedan is one hot ride that's available today.

In case you've forgotten, each of those brands started with a reputation for stylish two-seaters but had the courage to expand as the world changed.

I'm not the only one who believes expanding the Corvette line makes a lot of sense. General Motors Vice Chairman Bob Lutz told me that he has had the same notion.

Today, Lutz said, "Porsche is more than a car; it's a brand with coupes, convertibles, crossovers and, in the near future, a four-door sedan.

"You could do the same thing with Corvette."

But Lutz quickly extinguished the notion of separating Corvette from Chevrolet, saying GM has enough brands. To turn the Corvette into a separate brand today would be ridiculous, he said.

OK, Bob, so there's no need for a separate Corvette brand.

And the world has changed. Gasoline prices have soared, so there's little or no market for a Vette crossover.

S-t-r-e-t-c-h the Vette

Also, GM is wrestling with an expected rise in corporate average fuel economy standards, a likely reduction in CO2 emissions and the task of successfully completing its financial turnaround plan. Money is tight, and so are engineering resources.

Lutz didn't say whether a Vette sedan is being considered seriously.

But since the Panamera sedan is bound to be a home run -- ditto for the four-door Rapide -- there must be a market for a Corvette sedan.

We're not talking about creating a car from scratch. If Aston Martin can stretch the DB9, I know that Ed Welburn, Tom Wallace and their teams could do wonders if they were given the nod. Welburn is GM's chief styling guru. Wallace is the vehicle line executive for the Corvette and the Cadillac XLR.

Memo to Bob, Ed and Tom: Build it!

That triggers another idea. Once you stretch that vehicle architecture, there's an opportunity to use it to create a six-figure, extremely elegant yet sporty, beautifully detailed four-door Cadillac sedan. While we're dreaming, let's toss a supercharger on top of the engine.

That would give Cadillac something the brand desperately needs -- a flagship sedan.

But don't get me going on that subject.

You may e-mail Rick Kranz at rkranz@crain.com