Back at Ralph Lauren, a sales clerk drew Chen's attention to a red velvet jacket priced 3,000 yuan ($490) that, since the airing of a reality TV show featuring famous dads and their young offspring, has gained the cachet of celebrity status.

"It's the jacket Angela Wang wore on TV," said the shop assistant, referencing a widely viewed Ralph Lauren fashion show for kids.

Angela Wang, a.k.a. Wang Shiling, shot to fame in 2013 at the age of four while participating in the hit reality parenting program Dad! Where Are We Going? with her father, director Wang Yuelun. Her mother is television host Li Xiang.

Hunan TV acquired the rights to the popular Korean show of the same name and Wang subsequently became well-known for wearing outlandishly priced outfits in excess of 10,000 yuan, both on-and off-air.

Now China's one-child policy and growing ranks of high-net-worth individuals are dovetailing in just the right direction for the purveyors of kiddies' catwalk fashion.

"I used to buy a Birkin bag (Hermes) every year as a gift for myself," said Fang Jinqi, a 30-year-old mother of a two-year-old boy from Shanghai. "Now I spend half of that (about 100,000 yuan) on myself, and the other half buying luxury clothes for my son."

Numbers for this niche market are hard to come by－several brands declined to discuss their revenue and growth in China－but market players may need to be savvier in the future to keep up the tempo.

Financial results from Burberry show that children's products made up just 4 percent of its revenue in the yearlong period ending March 2012, making this the smallest contributor among its product lines. However, this line of revenue jumped 287 percent from 2006 to 2012.

"Differentiation and relevance are key challenges for luxury brands in the Chinese market in general, and in the kids' market in particular," said Calvar.

According to Zhou Ting, director of the Fortune Character Research Center, which covers the luxury industry, this segment will follow the broader pattern of quality coming to match prestige as the key yardstick.

"The high-end kids' market will get larger in the future, with more luxury items being produced for their functional and applicable advantages at an acceptable price," she said. "This will also open the door for newly launched domestic kids' brands."

Back at Plaza 66, one shopkeeper at French brand Bonpoint said: "We don't see huge traffic, but our customer base is more selective. Almost everyone who comes in buys something."

Some, like Fang, are drawn by the trophy-like nature of designer clothes, others by their inescapable cutesiness or Lord Fauntleroy-like regality. Few seem put off by the three-to-six-month lifespan. Safety is another consideration.

"Those well-known brands seem to be more reliable, of better quality and softer for a child's skin," said Sun Jia from Jiaxing in neighboring East China's Zhejiang province, who was shopping for her three-year-old granddaughter.

But some, like Zhou, caution against introducing notions of "status" into children's lives at such a young age. "It can have a negative impact on their growth," she warned.

Ironically, luxury-obsessed local shoppers may not be the kids-clothing retailers' next generation of cash cows.

"Most of our customers come from other wealthy Chinese cities," said the Bonpoint clerk.

Chinese now spend over three times as much abroad as they do at home on luxury goods, according to Bain & Company. Moreover, the people of Shanghai are known for their deal-loving dispositions.

"I fly overseas every month to go shopping－Hong Kong, Japan, Singapore－and since having my son I've found that luxury kids' items are also cheaper and offer a wider selection outside China," said local shopper Fang.

"I know the clothes won't last very long, but it's worth it so my boy can wear them, take some photos, and have some nice memories to look back on when he grows up."

Not everyone heralds the Chinese market for luxury kids' fashion as being the next big thing.

"I wouldn't say this is a particularly important trend that I've picked up on, but it's an interesting one," said Rupert Hoogewerf, publisher of the Hurun Report and its annual China Rich List.

"What we have noticed is these education advisers in places like Guangzhou (of Guangdong province) who are charging parents a small fortune to prime kids before the age of six to attend the best schools as they churn out future Xi Jinpings and Barack Obamas."