As the pie has grown, carmakers have done a better job of tracking down the newly ultra-affluent and convincing them to splurge on a space-age wedge of carbon fiber or a wood-paneled den on wheels. "It's been a pretty nice growth story," says BCG's Mosquet. "A lot of the growth has been triggered by new geographies."

China, in particular, has been ripe for rich rides. The country's share of the ultra-luxury car pie has swelled from 12 percent to 27 percent over the past five years, according to IHS. For Maserati and Rolls-Royce, China is now a larger market than all of Europe. Growth is also spreading across the rest of Asia and through the Middle East and Africa, regions where more people are hurdling over the $30 million mark faster than anywhere else, according to UBS and Wealth-X.

Not surprisingly, blue chip dealerships are following the money. Last year, for example, Rolls-Royce opened showrooms in both Cambodia and Vietnam. “Even if it’s only 20 or 30 millionaires in the whole country, these guys are thinking, ‘Maybe I should start buying the things to flaunt my wealth a little bit,’” says Ian Fletcher, an analyst at IHS Automotive.

Car companies are also doing a better job of price segmentation, the practice of separating customers by willingness to pay. For thousands of elite consumers, there's not much difference between spending $300,000 on a car and $1.2 million on a rarified version of the same kind of car. This explains the recent rash of ultra-expensive sports cars produced in small batches. Ferrari only made 499 of the LaFerrari, the surprise hybrid sports car rolled out at the 2013 gathering in Geneva. Each one had a price tag above $1 million. Porsche, meanwhile, made only 918 of its Model 918, a car that started at $840,000. Lamborghini bested them both, making just three of its 12-cylinder Veneno model and selling them for $3.9 million each.

The supercars that don’t aim for the top end of the speedometer, meanwhile, have focused on offering custom options. Four out of five Rolls-Royces sold last year went through what the car maker calls its "bespoke process." The coaches can be had with hand-engraved picnic sets, embroidered headrests, lambs-wool floor mats, and light-up hood ornaments. Rolls-Royce craftsmen will even stitch hundreds of diamonds into the ceiling lining to resemble a night sky—not just any night, but the constellation pattern evident on a specific date.

It’s not unusual for such extras to drive the price of a Rolls above $600,000. “We fulfill our owners’ desire to spend their money creatively,” Shepherd says. “If it makes the car totally unique, it’s much more valuable to them.”

IHS expects the super-premium car market to expand by an additional 21 percent in the next two years, and blue-blood carmakers may blow past that target if their plans pan out. 

Emboldened by their progress in emerging markets, nearly every luxury brand in the business is designing an SUV, an outbreak of product pragmatism that high-end brands once believed would ruin their finely crafted reputations. The very idea of Lamborghini making a vehicle for utility, rather than speed, is as scandalous to some as La Bernardin offering a gut- busting burrito. But the top of the car market is simply bowing to demand from buyers seeking bigger, boxier rides made by the brands they already favor.

Porsche has shown how easy it can be to make a pile from SUVs. The brand's biggest offering—the Cayenne—accounts for 35 percent of the company’s U.S. sales by vehicle, and adding a sport-utility option hasn’t soured drivers on its 911 sports cars. Porsche even doubled down on SUVs last year, rolling out a smaller model dubbed the Macan.

“The ultra-premium brands know what their customers want, and they’re going to give it to them,” says IHS’s Fletcher. “There are plenty of people around the world who will buy a Range Rover and go to someone that will double the price of the vehicle just by adding new paint and other things.”