It is sunset in your New York City high-rise. You have just finished mowing the lawn. Ten stories below you is the hum of the city traffic; to the north the elegant outline of the Empire State Building. If not for the crab grass, life would be perfect, buy why crab?

You lean on your picket fence, to watch the sun set slowly behind the World Trade Center. Your neighbor, the Doyle Dane exec comes by -- fresh from battle with the gypsy moths.

"Lunch," he says, "Call me."

"A yup," you say.

It's your own little mock-Tudor in the sky. Is this a fantasy, or can it be for real? Let us say simply it is a concept awaiting a developer. "Highrise of Homes," it is called, an idea from the iconoclastic Soho design firm of SITE Projects, Inc.

It was called "Sculpture in the Environment" when it was founded 11 years ago. Since then, it has designed, among other things, a Best Co. showroom in Towson, Md., with a tilting outer wall and another Best building in Richmond in which part of the structure is penetrated and enveloped by trees. Most SITE designs have been for Best, a catalog products company.

Recently approved, for construction in Washington, was a General Store faced with molded bluejeans.

"We were always told we were going to have trouble with vandals," says SITE senior partner James Wines, speaking of this and other projects. "Actually, we've never had any trouble with vandals. Most vandals know when they're outdone."

He says this in the ocmpany's offices in Soho, a renovated factory that bears the mark of Soho success: 18-foot ceilings, smooth tiles on the floor. Wines' offices, upstairs, are merely modern. He says the fact is that architects hardly ever live in their own work: It's too disruptive to new ideas.

He's hardly the stereotype of a slick architect, either. A large, bearded man, wearing black jeans, a black leather vest and a faded dotted yellow shirt that seems to date back to Carnaby Street. His background is as sculptor, and he is also, one quickly gathers, a theoretician. "Anti-architecture," is what he calls his work, and "anti-design."

He has a sharp, frequent laugh, which, like his buildings, may be a little strong for some people. Still, it is interesting: The splashy, laughing buildings have been designed by a splashy, laughing architect.

All of which makes one wonder: How serious is SITE about the Highrise of Homes?

Fairly serious, is Wines' reply, though interested developers -- of whom he insists there are several -- have yet to put their money down.

"People want the cultural advantages of the city, but they also want that little slice of surburban life. . . . They want a garden.

"There was a study done recently, and it showed that the frontier idea of domain is still alive in America -- of course there would be problems . . . and it wouldn't be cheap."

It would be, as it stands, extremely expensive. The costs, according to Wines, would be $150,000 for simply one's plot of high-rise lands; a total of about $350,000 when the two- or three-bedroom house is built.

The high-rise, Wines insists, would be as much like suburbia as possible: Inclined sidewalks, much like a spiral staircase, would transverse the 20-story buildings and the owners would be free to design their house in whatever style they choose. ("The ultimate anti-design project," he calls it, "because everyone would have freedom to do whatever they liked.")

Then there are the engineering problems, which SITE's engineer, Mathy Levy, has been grappling with for months.

"The service elevator would have to be extremely large," Wines said. "Think of what they'd be bringing up when people started adding on to their houses. . . . And you'd need extra light-weight concrete and an extremely strong steel frame.

"The weight of earth is triple the weight of the house -- and then you wouldn't want your neighbor's garden leaking through your roof."

It is sunset in your New York City highrise. The dashing stage actor who moved in next door is stretching his long legs out in the hammock you've stretched between your fine Red Maples. You are grilling steaks. The view from the eighth floor, as the sun sets over the Chrysler building is spectacular. Suddenly, the garden of your upstairs neighbor collapses on your lawn, burying the hibachi. A shattered jar of A-1 Sauce lays at your feet.

"Oh, wow," says the actor, through the hands he has raised instinctively to protect his nose. " i mean . . . can you believe it???"

"A yup," you say.