BY SANDRA BARERRA >Staff Writer

On a recent morning in Los Angeles, more than a dozen pint-size models sashay down the runway at Social Hollywood for a modest audience attending the preview to Baby Celebration L.A.'s "Sweet Petite Fashion Treats" show.

The ruffled diaper covers, plaid roll-up pants and splashy tutus elicit their shares of "oohs" and "aahs."

But when a 4-year-old girl with pompom pigtails emerges from backstage gripping in one hand a swirling lollipop and wearing a jaw-dropping whimsical outfit - described by its designer, Denise Love, as "a cross between `Sweeney Todd' and circus ringmaster" - the reality of it all sets in.

Haute couture for the sandbox set has arrived.

From Cookie magazine to last weekend's premier baby expo, a spotlight has been shining on this growing niche in recent years. The trend is part of what the Boston Consulting Group estimates is a $45 billion-a-year upscale baby market being driven by financially secure parents.

Patrice Meluskey, a co-founder of Baby Celebration L.A., says the obsession with celebrity is also nourishing the trend.

"The notoriety of celebrities having children has the public watching everything they're wearing and everything they're doing," she says. "Now people are dressing their children sort of like the celebrities dress their children."

It's true that discussions about which designer's work was seen on Suri Cruise and where to buy it have lit up the blogosphere. But Hara Estroff Marano, author of "A Nation of Wimps: The High Cost of Invasive Parenting," has her doubts that sites such as Baby Chic 101 are driving stampedes to the Beverly Hills boutique Bonpoint for $200 dresses.

She says the root of the widespread phenomenon is parental anxiety.

"The job of little kids - and big kids, too - is to explore the world, and it's a messy job, and they shouldn't be constrained by their clothing," Marano says. "It does tend to make them extremely conscious of everything that they put on their backs, and I don't think that's necessarily a good trend.

"But the part that's really so bad is that all of this is an extension of the parent's needs, not of the child's needs," she adds. "The anxieties of the parents to have the right stroller, to have the right clothes, to have the right shopping-cart liner ... should not contaminate the child."

Whether they're reflecting their social anxieties on their children or not, parents bombarded with the latest in fashion are buying into the hype. On Saturday afternoon, the Los Angeles Convention Center was crawling with families for Baby Celebration L.A.

Vendor booths hawked custom play structures, studio photography, strollers, retro tricycles, quilted cuddling sleeves, handmade jewelry, nursery furniture and more.

And there was plenty of high fashion being trotted on stage during the "Sweet Petite Fashion Treats" premiere for parents to gush over.

"There's more of a forum for fashion these days," says Aimee Baluyut, a first-time mom from Gardena who likes to comb the racks of boutiques and stores such as Babystyle for her 8 1/2-month-old daughter's wardrobe. She then peppers it with finds from Mervyn's.

While high fashion is the hot new trend, Baluyut says she believes it's here to stay.

"There are people who take a lot of pride in their children and they want to see them in something different," she says. "We all do that, whether it's buying your stroller or buying your clothes."

A report by the NPD Group shows that purchases of clothing for children (which includes babies and toddlers) is up despite waning consumer confidence.

"Times might be tough, but parents still want their kids to look cute," says L.A.-based designer and mom Erin Murphy.

Murphy's bright, colorful and vintage wallpaper print-inspired Baby Lulu line for girls and babies was among the more than 30 up-and-coming fashion houses and boutique children's designers spotlighted by Baby Celebration L.A., now in its second year.

Among this year's biggest trends is eco-friendly fashions.

Erin Cloke of L.A.'s Kicky Pants brought selections from her line of pleated dresses, coveralls with drop-down bottoms and ruffle-

bottomed onesies made of eco-friendly fabrics.

"I think eco-friendly has become really important to a lot of people, but I also think they're also coming to expect that there needs to be style involved as well," she says, singling out her pink ruffle-hemmed dress that Angelina Jolie just picked up.

Christina Aguilera and Halle Berry also have Kicky Pants pieces in their babies' wardrobes. Despite the celebrities who have gravitated to her line, Cloke says Kicky Pants is still relatively affordable, ranging from $16 T-shirts to $65 dresses.

Love, the North Hollywood-based designer who was behind the show-stopping Elizabethan ringmaster outfit and who runs Dandy Social Club, says she keeps her "fancy play clothes" affordable too. Her collection boasts a handmade flavor with thoughtful details and sturdy fabrics in floral, plaid and wood-grain patterns.

"It's like an Anthropologie for kids," says Love, who in September partnered with the Valley Village-based boutique Sandbox Rebel, where she now sells her separates and previews the coming season's line.

Many of the moms at Baby Celebration L.A. already are familiar with specialty boutiques such as Sandbox Rebel, as well as the growing number of high-end designers branching out into the baby and toddler market. Think Little Marc, Burberry and Cavalli for kids.

"There is this kind of Mini-Me phenomenon that's happening, and I think part of it is, why would you dress your kids differently than you would dress yourself, really? At least the style, and not necessarily the price point," says Pilar Guzman, editor in chief of Cookie.

Valencia mom Veronica Scott certainly wouldn't.

Scott, a former employee of Barneys New York who's about to launch her own fashion design business, called Tallulah Moon, for "the style-conscious baby," says there is nothing basic about the basic separates that are a part of her two daughters' unique wardrobes.

The 2 1/2-year-old ran around the Baby Celebration Gymboree play area in a brown baby-doll-style halter top and blush-colored skirt, while her infant sat in her stroller dressed in brown ruffle-hemmed pants and a floral top.

Sandra Barrera (818) 713-3728

The outfit above was created by Jodi Lee at Sandbox Rebel specially for the Sweet Petite Fashion Treats on April 8, 2008, in Los Angeles.  (Tina Burch/Staff Photographer).