This morning, interior decorator Barry Darr Dixon will unveil a glorious trophy house.

Dixon, who is known for over-the-top, lavish design, has envisioned room after room with color-infused, velvet-upholstered creature comforts. It would cost $7 million to duplicate the house's decor.

The McLean house--dubbed the "Capital Design House" and sponsored by Southern Accents magazine--is intended as a showcase of 21st-century style. When it opens to the public today, it will put Dixon, a leading Washington designer, in the national spotlight. Dixon was chosen for a simple reason: Southern Accents editor Mark Mayfield hails him as "a genius."

Six days before the Design House's first preview, the future dream house was still under construction. Dixon had pulled yet another all-nighter on the site, and the atmosphere was one of controlled terror.

On a warm, mid-October morning, a backhoe flattens clay on the edge of what will be the breakfast terrace. Plastic sheeting hangs where the house's front door should be. There is no running water, no phone. Inside, Dixon has worked for 48 hours without changing his jeans and shirt. He has gone 24 hours without eating.

"Sometimes, you have to punt," he says.

The Birmingham-based Southern Accents, a glossy proponent of Southern home style, will devote an 160-page special issue to the Capital Design House. Cable's HGTV will run fireside chats with Dixon this winter. "Good Morning America" has called. And the global elite of furnishings manufacturers--which includes fabric suppliers to presidents, kings and queens--will replay the decor in advertisements for months to come.

"It's a once-in-a-lifetime thing for a designer," says the 40-year-old Dixon, who picked up a modest flat fee--he wouldn't say how much--for the project, which amounted to a year's work.

Unlike fashion designers, decorators have not fostered a cult of celebrity. Other than New Yorker Mario Buatta, who achieved fame in the '80s as the "Prince of Chintz," none has become a household name. But in this new era of high-tech fortunes, decorators seem destined to come to the fore. "We're becoming respected," says Dixon. "Perhaps it's time."

The 12,000-square-foot house is modeled after Thomas Jefferson's Poplar Forest near Lynchburg, Va. Visitors to the house will notice the extraordinary placement of the dining room. The architect, Walter Lynch, designed an octagonal atrium in the center of the house onto which all rooms open. In other words, the least-used room in the American house today has been converted into a passage.

Dixon stands there now in stocking feet, pointing out an exquisite, fragile 1850 Murano glass chandelier worth $92,000. It hangs from a 39-foot-high dome. With carpenters hammering on the landing above, the chandelier is covered with bubble wrap. Without irony, Dixon calls it a "spiraling vortex."

At this level, interior design is like couture: nothing less than the pursuit of perfection, serenity through the exacting calibration of light, color, pattern and object. All around, 3,455 yards of textured velvets, silks and other fabrics, some retailing for $1,000 a yard, have been hung, draped and upholstered. In the golden music room, curtains are hanging in plastic. Painters are rolling a more perfect shade of imported English yellow paint on the ceiling.

Dixon likens his style to a blend of John Galliano glamour with the cool of Gucci's Tom Ford. In this conservative town, where beige interiors are considered bold, Dixon has used color fearlessly. Main rooms are painted brash shades of pumpkin, marigold, ocher and squash. The library is deep brown. A child's bedroom has dark aubergine walls and a candy pink ceiling.

Furniture ranges from theatrical to quaint--antique andirons shaped like sunflowers appear to grow along with vines on the 19th-century Arts and Crafts-style wallpaper. In the master bedroom, luminescent green walls are the result of hand-troweled plaster mixed with marble dust, a labor-intensive technique called Venetian plaster. The bed is stationed in the center of the room, to give its occupant the feeling of floating down a Venice canal. In the master bathroom, Dixon has imported Italian mosaic tiles that run up the wall to create the effect of a Pompeiian wading pool.

"He sees things larger than life," says Leslie Sadler, marketing director of the Washington Design Center. She recommended Dixon last year when the Smithsonian Associates needed a designer for a black-tie fund-raising gala. Dixon orchestrated the transformation of the center's loading dock next to the rail tracks into a replica of the Paris Ritz hotel lobby. Only a passing freight train reminded partygoers that they were sitting on a grim city street. Dixon had cosseted them softly in 4,600 yards of imported cotton toile, tented and embellished further with opera props.

Late at night in the McLean house, Dixon's muse has been working overtime. There is no question in his mind that he will finish the decoration on time. Weeks behind because of construction delays, he still devotes hours to the tiniest details.

In the library, the casual observer may notice a portrait of Baudelaire, but miss the book on the table below. Borrowed from an Atlanta dealer, it was owned by the French poet and contains Baudelaire's own handwriting. Opposite, on another table, Dixon has placed a bronze sculpture titled "Thinking Gaul." He chuckles as he wonders how long it will take a visitor to connect the visual links.

Dixon's father was a metallurgist from Memphis whose work took the family to New Caledonia and South Africa, India and South Korea. But the family always returned to the South: New Orleans, Mobile and near Oxford, Miss.

The decorator's mother passed on her love of antiques. He soaked up old Hollywood glamour from movies and a sense of scene from journeys abroad.

Dixon earned a bachelor of fine arts in art history and design from the University of Mississippi in 1982, then settled into the world of interior design. Moving here from Jackson, Miss., he landed work with two well-known designers, Carol Lascaris and the late Bob Waldron. By 1986, Dixon was participating in Entertaining People, a high-profile designer charity that raised money for a local hospice. He began appearing in National Symphony Orchestra annual show houses while working for Interior Concepts in Annapolis in 1990. In 1995, Southern Accents tapped him for its "Top Four Under Forty" list.

Working under his own name for the past five years from an office on Q Street NW, he has designed houses for private clients, law and accounting firm interiors and an office at ABC for Diane Sawyer. A project for Sen. Bill Frist (R-Tenn.), a longtime client, became the cover of a Southern Accents Christmas issue.

Norma and Russ Ramsey, whose business involves handling IPOs for high-tech companies, first met Dixon in 1991. He has since designed three houses for them.

"Those high-tech clients, they need a Barry Dixon," says Norma Ramsey. "These people are so busy, moving into a house twice the size. They need help transforming from their old lifestyle to the new."

The Ramseys' Great Falls living room, filled with Italian and French antiques, is like "a palace 200 years ago," she says. In the living room, Fortuny draperies woven with gold, silver and chartreuse threads are set off by painstakingly stenciled walls that have been speed-aged with faux water stains. "His strength is that he's historically correct, then he throws in flair," she explains.

Dixon's own house, on Upper 16th Street NW, has remained a work in progress, a victim of the decorator's own success. Partner Michael Schmidt describes it as layers of show houses past. It is a storehouse for props. It has also been a stage set for the annual Christmas tree on which Dixon personally wires 5,000 lights.

The house is for sale. Dixon is moving to the Virginia countryside, which would mean an easier commute to McLean or Middleburg, where trophy houses are being built.

Ultimately, Dixon's vision of the Capital Design House will be as fleeting as the autumnal leaves painted on its dining room walls. They will shimmer through Dec. 5, until someone turns out the lights of the borrowed chandelier.

"Let it be known," says Dixon, "that none of this was done without great effort."

For visiting hours and other details, call 888-212-7050 or see www.southernaccents.com. Barry Darr Dixon will be live online on washingtonpost.com tomorrow at 2 p.m.

CAPTION: Place setting: Decorator Barry Dixon in the dining room of the Capital Design House.

CAPTION: "It's a once-in-a-lifetime thing for a designer," says Barry Dixon of his work on the Capital Design House.