What Now, Design Darlings? : First Lady fave Randy Kemper has one thing on his mind--working women with no time to primp.

NEW YORK — For nearly six years, Randy Kemper has been designing sleek, tailored separates at less-than-Midas prices--$150 to $450--that have attracted a legion of fans, mostly peripatetic working women who have more on their minds than their next manicure.

His calm, wearable clothes have provided little grist for glossy spreads in Vogue or attention-grabbing windows in SoHo boutiques. He has never held a major fashion show, and his name is virtually unknown at the trendy watering holes frequented by Calvin, Donna and other star riffraff.

But that was BC, Before Clinton, or, more specifically, before Hillary Rodham Clinton started sporting Randy Kemper outfits on the campaign trail--and ordering half a dozen more since moving into the White House. (She posed for a recent Redbook cover in his red crepe suit with little gold buttons.)

Since then, the style gurus at Vogue and Women’s Wear Daily have come calling, People magazine has tapped him for its “Fifty Most Beautiful People” issue, his company is relocating to larger, plusher headquarters and he will stage his first New York fashion show later this month during the fall collections.

“I’m not upset that it took Hillary to get me noticed,” he says good-naturedly. “In fact, it happened at just the right time. If you’re heralded too early by the press, you don’t have time to grow and develop. Now, I feel I’ve matured, that my collections are more consistent.”

Sipping a Diet Coke in a cubbyhole office of his soon-to-be vacated, cramped showroom, Kemper is funny and relaxed and seems more amused than self-aggrandizing about his newfound fame. Tall and tanned (from a recent weekend in Miami), the boyish-looking Kemper, 33, could pass for a television anchor if it weren’t for his little hoop earring, Don Johnson-style stubble and black sweater and jeans, the industry uniform.

Asked about his fashion philosophy, he’s quick to say he isn’t interested in designing “$2,000 dresses for women who are 6 feet tall with Size 4 hips.”

“It’s not reality,” says Kemper, whose clothes are carried by Neiman Marcus, Saks Fifth Avenue and Bloomingdale’s. “Designers who live in New York and design for New York trendies are living in a vacuum. You have to sell to Kansas City and Cleveland if you want to stay in business.”

He says that Clinton, a working mother with a Size 8 figure, is the “perfect role model” to wear his easy jackets with elegant details like velvet collars and silk print linings, long slim skirts and fluid trousers. (So far, she hasn’t ordered any pants, but Kemper is confident she will.)

Amazingly, he has never met the First Customer.

“We’re getting close, though,” he says, adding that he plans to invite Clinton to his fall show. “Her office called and asked for photographs of the spring collection so she can order. It’s not like she has the time to come for tea and try on clothes.”

In 1987, he launched his company. His sister, Lynn, a former Wall Street financier, is CEO, and a London investment firm is his backer. Last year, Kemper’s sales hit $15 million.

His plans include a division of casual weekend clothes and perhaps a line of belts and accessories. But for now, his attention is focused on his March 31 runway show at his new, airy, Seventh Avenue headquarters.

“Anyone can hire the most beautiful 20-year-olds to walk down the runway, and they’ll look awesome,” he says, “But I don’t think my customer is about that.” Instead, Kemper says he’d like to have fortysomething model Dayle Haddon and silver-haired Carmen join the usual brigade of young sylphs.

What Kemper doesn’t plan to change are his prices, which he aims to keep below the stratospheric level of, say, Donna Karan.

“Anybody can make a $1,600 jacket,” he says. “The challenge is to make a $400 look like a $1,600.” He puts down his Diet Coke and grins. “But believe me, it can be done.”