There has been a significant drop-off in the sales of large SUVs since gasoline prices went through the roof a few years back. Inventories continue to pile up on dealership lots, and manufacturers are laying on heavy incentives to move not only the leftover 2006 models, but also the new 2007 models.

However, the inventory of large luxury SUVs isn’t nearly as deep. In fact, sales of those expensive, limited-production vehicles are growing, and there are a number of new entries into the segment.

For this test, we chose the new Mercedes-Benz GL, Mercedes-Benz R-Class, and Audi Q7. We also tested the redesigned Cadillac Escalade and freshened Volvo XC90. Prices ranged from $47,685 for the Volvo to $67,820 for the Mercedes GL.

The Mercedes GL450 is based on the smaller ML but offers standard seating for seven passengers. While the GL is longer than the ML and provides generous interior room, its exterior dimensions are relatively modest. Both the second- and third-row seats are roomy and comfortable. Towing capacity is impressive, the cabin is quiet, and handling is nimble and secure. We chose typical options that usually come on the GL, including the rear entertainment package and the navigation system. A diesel version of the GL will be available in 2007.

Pigeonholing the R-Class into one category doesn’t work. It’s not a true minivan, but it isn’t an SUV. What the R-Class does is provide speedy, luxury transportation for six passengers in a quiet, roomy environment. Like the GL, the ride is comfortable, but it’s not as agile as its larger sibling. The long rear doors help access to the rear but are a liability in narrow parking spaces because they swing out very wide. When the rear seats are folded, the R-Class seats only four people. We added a navigation system and a large sunroof, among other options, to the vehicle in our test. A less expensive version, the V6 R350, is currently available and a diesel-powered version is scheduled to arrive in dealerships in 2007.

The Volvo XC90 has always provided a comfortable, flexible interior and extensive safety features, but the underpowered engines and below-par reliability have been big disappointments. The addition of a Yamaha-built V8 engine provides better performance, refinement, and slightly better fuel economy. We outfitted our XC90 with the climate package, which adds heated seats and headlight washers.

Audi is a latecomer to this field and its new Q7 shares some underpinnings with the Volkswagen Touareg and the Porsche Cayenne. However, it’s slightly longer than those vehicles and comes with a standard third-row seat.

The interior is very well finished, but the Q7 features the complicated Multi Media Interface (MMI) driver interaction system and the vehicle’s heavy weight takes a toll on acceleration. Fuel economy is 15 mpg in mixed driving. Modest cargo space and poor rear visibility are annoyances, and the slow-to-react stability control system of the Q7 hurts it as well.

We added a rear-view camera, blind-spot detection system, panorama sunroof, and some other options, but our expensive Q7 still lacked the GPS navigation option. A less expensive version of the Q7 with a V6 engine arrives in dealerships in 2007.

The Cadillac Escalade is a big, showy sport-utility vehicle that has carved a hip niche for the brand. It comes with a standard 6.0-liter V8 engine and a six-speed automatic. Like its sibling, the Chevrolet Tahoe, which we tested in July 2006, the third-row seat is quite cramped, even for children. And while the Escalade has more features and better quality materials than the much less expensive Tahoe, it offers little fundamental advantage. Handling for the Escalade is clumsy, braking is below par, and fuel economy is poor. We added the information package, entertainment system, and second-row power release, among other options, on the Escalade in our test.

Wagons are a practical and often less expensive option to SUVs, and we tested four AWD models for this month.

The Volkswagen Passat 3.6 4Motion, BMW 325Xi, Subaru Outback 3.0 R, and Volvo XC70 are wagon versions of sedans we have recently tested and the reviews serve as an update to our previous tests.

Each of the wagons provides cargo versatility, better mileage than most SUVs, and seating for five passengers (the Volvo also offers a kids-only third-row seat). Prices ranged from $36,480 for the Passat to $43,205 for the XC70.