When the 2002 Chevrolet TrailBlazer sport utility vehicle was introduced a year ago, quite a few potential customers thought something was missing: a third row of seats.

After all, the similarly new-for-2002 Ford Explorer, and its stable mate, the Mercury Mountaineer, offered third-row seating. The Explorer was 189.5 inches long, and the TrailBlazer was 191.8 inches long – how could Ford fit three rows of seats, and Chevy couldn’t, even though the TrailBlazer was more than 2 inches longer than the Explorer?

If you ask General Motors engineers – and I did – they’ll tell you that it was certainly possible to put a third seat in the TrailBlazer. The Suzuki XL-7 has a third row of seats, and it’s only 183.6 inches long.

It’s just that Chevrolet thought that if the TrailBlazer was lengthened by 16 inches, you’d have room for a third seat and still have enough room behind the third seat for cargo, luggage or golf clubs.

So the automaker did. There’s still the five-passenger TrailBlazer, but just introduced is the seven-passenger TrailBlazer EXT, as in “extended.” The GMC Envoy, a twin to the TrailBlazer, also gets a seven-passenger model called the Envoy XL – “extra length.” The lame-duck Oldsmobile Bravada doesn’t get stretched, and may not even after it becomes the Buick Rainier for 2004.

The TrailBlazer’s 113-inch wheelbase (the distance from the center of the front wheels, to the center of the rear wheels) was stretched to 129 inches for the EXT model. The EXT weighs 4,836 pounds, 429 pounds more than a comparable five-seat TrailBlazer. Which begs a question: Why not go ahead and get a full-sized Chevrolet Tahoe? Though it is available with optional third-row seats, the Tahoe is 9 inches shorter than the TrailBlazer EXT, and comes standard with a V-8 engine.

Personally, I’d take the Tahoe. However, judging from the reaction the test TrailBlazer EXT received, that is hardly a unanimous opinion.

The EXT does indeed make excellent use of space. At 6 feet tall, I fit comfortably in the third row, and because the second-row seats easily tumble forward out of the way, getting back there was easy. The two third-seat passengers get their own flip-out window, cup holder and air-conditioning vent.

There’s a healthy 22.3 cubic feet of space behind that third seat, bigger than a Lincoln Town Car’s trunk. Fold down the third row and cargo space reaches a minivanlike 61.6 cubic feet.

The EXT’s extra length and weight make for a smoother highway ride, but much of that weight seems concentrated at the rear, making the EXT feel tail-heavy. Otherwise, handling was good, but backing up, you are conscious that the EXT is longer than every SUV but the Chevy Suburban, GMC Yukon XL and Ford Excursion. The 270-horsepower, inline six-cylinder engine handles the extra weight well, aided by the excellent four-speed automatic transmission. The test EXT was two-wheel-drive – four-wheel-drive adds another 194 pounds, and with a full load of seven people, you’re asking a lot from a six-cylinder engine.

The TrailBlazer EXT tested lists for a reasonable $31,850 and had every feature I’d want. If you need seven-passenger seating, the anti-minivan EXT was worth the wait.

Base price: $30,785.

As tested: $31,850.

EPA-rated mileage: 15 mpg city, 20 highway.

Details: Rear-wheel-drive, 7-passenger ** sport-ute, ** sport-ute 4.2-liter, 270-horsepower 6-cylinder engine, 4-speed automatic transmission.