“For Sale” signs are all over the Hamptons, signaling loud and clear that even New York’s summer playground for the rich, the famous, and the infamous is not impervious to a nationwide housing slump.

While some real estate brokers there tell me the current market is pretty lively in both sales and rentals, given the proliferation of lawn signs and a general housing slowdown, why would two real estate pros, brothers Frank and Roy Dalene, launch a daring new venture, the Hamptons Real Estate Fund LP?

The Dalenes are principals of Hamptons Luxury Homes, a company engaged in housing construction and maintenance services. About 75% of its business is done with Wall Street clients, who include top moneymakers at Goldman Sachs and Bank of America Securities.

The new fund is off on what seems a Mission: Impossible — raising $100 million from just 100 investors. The Dalenes, the general partners of the Bridgehampton, N.Y.-based fund, are offering just 1,000 partnership shares at $100,000 a share.

That ought to add up to way more than 100 investors, but as the Dalenes explain it, “We want to confine the number of investors to a strict 100, and we’ll be looking to those who can buy 10 or more shares at a clip.”

A big plus, they believe, could be strong Wall Street participation, spurred by 2006’s estimated $24 billion in Wall Street bonuses.

Money raised by the fund will be used to acquire prime older properties, as well as land, in the estate sections of Southampton and East Hampton, primarily properties with water views. The existing houses will then be torn down and rebuilt to customer specifications (no spec houses will be constructed) at price tags that will likely range between $15 million and $60 million. The average price is expected to end up somewhere between $20 million and $30 million.

Because it takes six to eight months to redesign acquired properties and obtain the necessary building permits, the partnership in the interim will seek to generate additional income by renting out the existing homes for between $100,000 and $300,000 for three months.

The bulk of the partnership’s income is expected to come from realizing a 40% premium above the cost of the property and construction in an ongoing strong market.

Whether the Dalenes can raise the $100 million to fund their plan is anybody’s guess, but, interestingly, they tell me that they’re presently talking to a hedge fund organization that may buy the fund’s entire 1,000 shares.

Why would anyone do that with all those “For Sale” signs around? “That’s the middle market you’re talking about,” Roy Dalene responded, referring to homes in the $3 million to $8 million range, “not the upper market we serve” — homes priced at $10 million and up. “There are no ‘For Sale’ signs in the upper market,” Roy Dalene said.

A broker at Brown Harris Stevens of the Hamptons and an area appraiser, John Watson, describes current activity as reasonably strong at all price levels, and notes that good rentals are difficult to find. Prices are about on par with last year, Mr. Watson estimates, when they rose around 10%. The only weakness he sees is in the market for first-time home buyers (under $1 million), which is feeling the impact of rising interest rates; he finds a brisk demand for homes in the $1 million-to-$3 million and $7 million-to-$10 million categories.

Buoying the market, Mr. Watson said, are the many renters who have turned into buyers. Likewise, he sees a growing global presence in the Hamptons, sparked by the weak dollar, which is encouraging a growing number of European and some Asian buyers to buy in.

So what about all those ‘For Sale’ signs? “Those signs are all over America,” Mr. Watson said. “I can only tell you every broker here is busy, we’re getting lots of phone calls, and I’m getting lots of appraisals.”

In an intriguing luxury housing sidelight, the New York City’s last three biggest co-op sales all involved apartments owned by members of the Rockefeller clan.

The three, according to Denise Lefrak Calicchio, author of the recently published inside look at the city residences of the rich and famous, “High Rise Low Down,” were: Blackstone Group chief executive officer Stephen Schwarzman’s 2000 purchase of what had been John Rockefeller’s 37-room triplex at 740 Park Ave. for $32 million; the 2006 sale of Nelson Rockefeller’s 11-room apartment at 810 Fifth Ave. to film producer David Geffen for $31.5 million (reportedly now being sold to a Blackstone Group founder, Peter Peterson, for an estimated $34 million), and Rupert Murdoch’s 2004 purchase of Laurence Rockefeller’s 20-room triplex at 834 Fifth Ave. for $44 million.

Speaking of Mr. Murdoch, who recently made a $5 billion bid for Dow Jones, an attorney close to the publishing firm’s controlling Bancroft family told a Wall Street contact that Mr. Murdoch has about as much chance of buying Dow Jones as he has of buying Exxon Mobil.