Move over, Jed Clampett.
A half-century after "The Beverly Hillbillies" made light of the rich and famous, Beverly Hills is about to celebrate its centennial. These days, however, the wheels of commerce along Rodeo Drive are no longer greased by oil money ("black gold, Texas tea") or by much American money at all.
Most of the revenue now comes from international tourists, and one country in particular dominates the landscape. According to a study commissioned by the Beverly Hills Conference and Visitors Bureau, about 60 percent of the revenue is coming in from foreign tourists.
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"I would say that as much as 60 percent of our business in some stores—and even some stores might report more than that—comes from Chinese shoppers," said Julie Wagner, who runs the bureau. Chinese alone account for 60 percent of sales on Rodeo Drive, according to the study.
"The Chinese market is growing," said Efrem Harkham, president and CEO of Luxe Worldwide Hotels, which opened on Rodeo Drive 20 years ago. In fact, he said, no longer are Chinese tourists coming to shop by the busload. "The younger ones are now doing it on their own," he said.
Wagner agreed.
"The 25- to 37-year-olds are finding their way out and doing it personally, privately," she said. "We continue to see a shift from people who come and don't stay—they just visit us for the day—to people who are now starting to stay in our hotels."
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Earlier this year, LVMH warned of a slowdown in luxury spending inside China, but Harkham and Wagner said it hasn't made its way to the U.S. side of the Pacific yet. Sales tax receipts are up 10 percent from a year ago, and room rates at the Luxe Rodeo Drive Hotel are up about the same.
Beverly Hills benefits from other foreign tourists—Harkham said 15 percent of his clients are from Australia. Wagner said the city continues to see a large influx of shoppers from the Middle East, "especially during the summertime when it's so hot over there."
It's not unusual to see large Boeing business jets parked at LAX that are owned by rich Saudi families visiting just to shop.
Perhaps some will join the expected crowd of 15,000—mostly locals—who will enjoy a massive block party Sunday along Rodeo Drive. Four-story ferris wheels, food from famous chefs and a cake in the shape of city hall will be part of the birthday celebration.
Pastry chef Donald Wressell of Guittard Chocolate has spent almost a year planning the cake, which will measure 12 feet wide by 24 feet long and rise 9 feet at its peak.
"It's actually chocolate cake, white chocolate buttercream, chocolate flour, and we made the top of the cake look a little bit like asphalt on the street, because we're going to put a lot of buildings on it."
The buildings will be made up to look like edible shopping bags.
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Whether the Chinese slowdown hits a place like this, which defines itself by luxury, the public face of Beverly Hills does not appear worried at the moment.
"The international market is willing to pay," said Harkham. "They realize the American product is still very affordable."
Affordable and Beverly Hills in the same paragraph? What would Jethro say?
—By CNBC's Jane Wells.