The poshest room in the hotel -- the so-called presidential suite -- is getting its own upgrade.

Many hotels have long promoted their largest, most glamorous suite as the place to house moguls, celebrities and even actual presidents in the utmost comfort. Now, with competition in the U.S. hotel industry escalating as room supply continues to grow and demand slows, hotels are putting more glitz into their top suites. They hope to use the suites to woo not only those rich enough to afford their eye-popping prices -- $30,000 a night in some cases -- but also to generate buzz around their entire properties. The promise is that presidential-suite glamour may just rub off on those booking regular rooms.

Ty Warner, the toy mogul and owner of the Four Seasons Hotel New York, invested $50 million in that hotel's top-tier suite, the Ty Warner Penthouse. The suite opened last summer and is home to an indoor-outdoor "zen garden" that overlooks downtown Manhattan and a bathroom sink carved from a solid block of rock crystal. Raffles Dubai opened two "royal suites" in February. Intricate stone inlays line the walls of one, terracotta statues the other. Both have dining rooms for 12 people and come with a personal butler. The Ritz-Carlton Washington D.C., which has its eye on this winter's presidential inauguration, completely renovated its luxury suites at the end of 2007, adding larger TVs with access to more international stations and additional seating in the living room and dining room to accommodate large in-room diplomatic meetings.

The hotels say the rooms and the personal service guests in high-end suites receive are worth the investment. An impressive suite "allows you to reach that top-tier market," says Jorge Collazo, director of sales and marketing for the Setai hotel in Miami. The hotel's penthouse has a private roof-top infinity pool, a Steinway piano and costs $30,000 a night. "It will attract guests who want the penthouse and travelers to our other suites too," because of the good reputation the suite gives the entire hotel, he says.

These rooms aren't for the price-sensitive. The Royal Suites at the Raffles Dubai cost $12,252 a night. The Ritz Carlton Suite in D.C. is $5,800 per night, and the Ty Warner Penthouse is $30,000 a night.

Four Seasons Hotel The Ty Warner Penthouse at the Four Seasons Hotel New York rents for $30,000 a night.

But not every guest has to pay those presidential suite prices. At the Four Seasons Hotel Westlake Village in California, the presidential suite is often free or discounted for meeting planners looking at the location for an event, says Thomas Gurtner, the hotel's general manager and regional vice president. In addition, "if a PR person or celebrity stays that we can position ourselves with, we sometime upgrade them as a surprise," he says. The suite includes a dining area with hand-painted silk wall coverings. The adjacent kitchen with pantry is equipped with refrigerated wine storage, a Sub Zero refrigerator and granite countertops.

And the president himself doesn't pay the rack rate -- at least not at the Waldorf-Astoria in New York -- where the presidential suite has hosted every seated president since Herbert Hoover, says Matt Zolbe, director of sales and marketing for the hotel. "If the president stays here, other heads of state stay here, and then so do international business heads," so the president provides unlimited marketing value, Mr. Zolbe says. The president always negotiates a government rate on an official trip when possible, says White House spokeswoman Emily Lawrimore. Hosting presidents at the Waldorf is so common that before a president's visit, the phones can be quickly changed to mirror the phones in the White House. If #2 normally rings the First Lady, #2 on the suite phone does the same.

Regular Joes do get upgraded to the top spot every so often. "If someone walks in at 11 [p.m.] and it's open that night, they might get lucky," says Mr. Gurtner of the Four Seasons Hotel Westlake Village. At the Waldorf-Astoria, a regular who is known to get in late at night and leave early in the morning, might get put into the presidential suite as a perk.

"He's paying 1,200, 1,400 bucks" for the $7,000-to-$10,000 suite, so it's an acceptable discount, explains Mr. Zolbe. "He is going to call his wife and say, 'Know where I am tonight?' Sleeping in the president's bed.' "

A few hotels say they stick religiously to their listed price. The Ty Warner Penthouse "is the only suite in the hotel that I can genuinely say has never been discounted," says Leslie Lefkowitz, director of public relations for the Four Seasons Hotel New York. It is rented about once a month, she says.

Concorde Hotels & Resorts The Penthouse suite of the Hôtel Martinez in Cannes costs about $47,000 per night.

The suites also bring in lucrative meeting and conference business. Richard Coon, president of the Recreational Vehicle Industry Association, has stayed in many presidential suites during his organization's meetings. As part of the meeting contract, the group is usually given the top suite for the price of a regular room. Walking down the hall at the Fairmont Orchid at Mauna Lani, Hawaii, during a recent stay in the presidential suite for a meeting, "the maid called me by name," he says. "How do you not love that?"

Even if you're asked to -- and can -- pay full price, that doesn't mean you can book the suite. In an attempt to protect all those expensive furnishings, hotels do turn down potential guests who they perceive could be destructive or rowdy -- perhaps by surreptitiously sneaking in 100 of their closest friends for a presidential-suite bash.

If a guest is not known to the hotel or not booking through a known travel agent, movie studio or meeting planner, the hotel will make extra efforts to check them out. First, most hotels require that their top suites be booked through the general manager's office or a designated office.

At The Dorchester in London, all reservations for the royal penthouse must go through a designated booking office, and if the guest is unknown, the hotel will make a point of checking the guest's credit-card limit, says Brett Perkins, the hotel's sales manager. The suite -- with a 24-carat gold plate and black marble bathroom, along with a hairdressing room and cinema -- is listed at £15,000 (about $30,000) per night, plus VAT of 17.5%.

At the Waldorf-Astoria, special security checks are done on an unknown guest attempting to book the presidential suite, especially if diplomats are staying in nearby rooms. "We have a good relationship with homeland security," Mr. Zolbe says.

The Setai, South Beach The roof top of the Penthouse suite at The Setai hotel in Miami has a private swimming pool.

Pure marketing is also a concern when deciding to book a suite. The Waldorf-Astoria will hold its presidential suite if a guest doesn't fit the room's profile. "We don't want to make it easily accessible because then it loses the mystique," says Jasmin Howanietz, who is often in charge of booking the room as the director of diplomatic affairs for the hotel. If an unfamiliar guest calls to reserve, she will ask a series of questions to get an idea of how the room will be used. If the potential guest is a businessperson, Ms. Howanietz says, she often checks out the person's company online.

Fending off known suite-trashers is important because many top suites hold rare art work or delicate fabrics like silk carpet with gold embroidery. "If you have been in the business for a while you know" who has a reputation for damage, explains Mr. Gurtner of the Four Seasons. "We will find a way to convince them it's full."

Those who do get to book the presidential suite are partly lured by the promise of privacy. But that doesn't always work so well -- and hotels admit that they like the publicity a high-profile guest courts. Any employee who talks to the press about a guest's identity at a Ritz-Carlton is disciplined, says Vivian Deuschl, vice president of public relations for Ritz-Carlton. But, she adds, "if it gets in the paper" that a diplomat or celebrity stayed at a hotel, "it adds cachet."

Since most properties have just one top suite, hotels often find themselves having to choose between two high-profile guests who want the same room. The El San Juan Hotel and Casino in Puerto Rico gives the nod to high rollers over pop stars. "High rollers are better than celebrities" because they spend more money, explains managing director John Paul Oliver.

If the president needs the presidential suite at the Waldorf-Astoria, he gets it no matter what. After him, next in line are "a couple of Middle Eastern delegations," says Mr. Zolbe. The hotel will find another room for the person in the presidential suite during an unexpected stay from these priority customers.

--Darren Everson contributed to this article.

Write to Sarah Nassauer at sarah.nassauer@wsj.com

Hampshire Hotels to Develop 2 New Projects in Kochi

American Girl Founder Puts Houses on Sale

Ceilings Come Down to Earth