Many of them have carpet, heating and air-conditioning, indoor and outdoor lighting, and elaborate music and entertainment systems. Some are even eco-friendly, with solar panels or green roofs.

In fact, the only superfluous accessory in the modern doghouse may be the dog.

Take, for instance, the Palladian-style mini-mansion that Glenna and Ed Hall bought at a charity auction three years ago for about $300. With Jeffersonian columns that match the ones on their home in Roanoke, Va., the 2-foot-tall doghouse makes a perfect accent for the garden. No one seems to mind that the garden is off-limits to Maggie May, their 28-pound whippet-borzoi mix -- least of all Maggie May.

"We bought the house because it looks a lot like our house," said Glenna Hall, a retired interior designer. "Maggie's never been in it. She's a house dog."

Traditionally, doghouses were where dogs actually lived, separate from the family. But now that dogs are increasingly considered members of the family, their homes are becoming more like second homes -- and in some cases, they're entirely ornamental.

Sure, there are still plenty of doghouses built for dogs to live in. But there are also an impressive number built the way Christian Louboutin makes shoes: You can walk in them (sort of), but clearly that's not the point.

As Michelle Pollak, an interior designer who creates custom doghouses under the name La Petite Maison, said: "Half our clients say, 'Hey, we'd like a replica of our home for the dog,' and half say, 'This is the dream house we've always envisioned but couldn't afford in real life' -- like a French palace for the French poodle."

No detail is too small, right down to the hand-painted portrait of the dog in residence. For supermodel Rachel Hunter's showpiece doghouse in Los Angeles, Pollak supplied a hand-painted wallcovering dotted with pawprints and bones, as well as framed pictures of dogs. Her business partner, builder Alan Mowrer, installed wrought-iron light fixtures and terra-cotta flooring.

"Alan had to hand-make every tile of the Mediterranean roof," Pollak said.

The average price of their doghouses is about $5,000 or $6,000, she said, although it is not unheard of for people to spend more than $25,000.

Another client, Guillermo Gonzales, is an entrepreneur who lives outside Austin, Texas, in a 5,000-square-foot Victorian-inspired home with four pet pigs. The "boys," as Gonzales refers to them, are 4-year-old Vietnamese potbellieds, Augustus (120 pounds) and Vito (95 pounds). They live in a specially built 300-square-foot addition to the house furnished with hay and blankets.

But the "girls," Cherry and Abby, 6-month-old micro-minis that weigh 7 pounds each, sleep in a 6-foot-square replica of Gonzales' home that sits in the corner of his safari-themed living room, not far from taxidermied busts of a zebra and an impala.

"The corner I put it in, it looks like kind of a plantation farm in a safari in South Africa," Gonzales said.

'Waste of money'?

Such excess can be an invitation to criticism, but Pollak offered a quick rebuttal.

"People will come and say, 'This is such a waste of money, why would anybody do this?'" she said. "All I can say is that if you have the money, what's the difference between spending it on a pet house or on a piece of diamond jewelry?"

Besides, she said, many of her clients build houses for dogs they have either rescued or adopted from shelters. One client, in fact, had a disabled rescue dog for which Pollak and Mowrer created a handicapped-accessible home.

"Alan adjusted all of the windows and the doors to allow the dog to see out the window," she said, "even if he was lying down."

Doghouse design tends to be popular with architects and builders, who sometimes refer to it as "barkitecture" and donate their creations to charity auctions that raise money for animal shelters. Designers say they love doghouses because they're small and fun and allow lots of room for creativity.

As Brian Pickard, an architect in Philadelphia, put it: "If I build a doghouse and somebody is anticipating that it's going to last 10 years in their back yard, it's different from designing a house that somebody is expecting will last for 50 years. I can be more experimental."

For dogs that don't spend even part of the day outdoors, there are still plenty of choices. FormaItalia, a division of the Italian furnituremaker Chiavari, sells lacquered indoor kennels and pet beds that can be suspended from the ceiling. Denhaus, a company in Seattle, makes dog crates disguised as household furniture. The Townhaus, a square wooden table, doubles as a holding pen for naughty puppies, and the BowHaus, a circular silver cocktail table, can hold drinks on top and a dog inside.

M. Brandon Smith, who owns a wine company called Small Cellars, bought one BowHaus for his home in Birmingham, Ala., and another for his lake house after he and his wife, Kim, got a small fluffy dog for their 5-year-old son.

"I had absolutely no interest in putting a regular plastic crate in either of the houses," Smith said, adding that the dog, Margaux, a Coton de Tulear, retreats happily to the designer crate, which is centrally located in both houses, in the living and dining area.

The family entertains frequently, and the doghouse is a conversation piece.

"People just think it's a coffee table," Smith said. "And then 20 or 30 minutes later the dog goes in there, people will realize, 'Omigod, it's a crate.'"

Barbara Dalhouse, president of the Roanoke Valley SPCA in Virginia, keeps her Hobbit-style wooden doghouse inside because it is "too beautiful," she said, to put outdoors. Carved from a log retrieved from a swamp in New Orleans after Hurricane Katrina, the 50-inch-tall shingled hut is topped with an acorn and "looks like a gnome would live in it," she said. But the sole resident is a stuffed squirrel.

"The cats look in every now and then," she said. "And Lucy the beagle walks by. But they say, 'Uh-uh, we're couch people.'"

Hugo, a white French bulldog in Mill Valley, Calif., has a similar attitude toward his eco-doghouse, a designer structure complete with a green roof.

"It's hard to get a dog to love the doghouse," said Eric McFarland, a real estate agent who owns Hugo with his spouse, Brad Krefman, an interior designer. "He'd rather be in our bed."

What recession?

While the market for high-end doghouses is, understandably, a limited one, those who sell them say that, despite the recession, business has remained steady.

The Little Cottage Co., in Ohio, makes some of the most picturesque doghouses available online, including the Victorian Cottage Kennel Dog House (about $4,000 at Walmart.com) and the Cape Cod Cozy Cottage Kennel Dog House (about $4,350 at Walmart.com; prices vary depending on the seller). Dan Schlabach, who owns the company, estimates that he sells 10 to 15 a year, a number that has remained fairly consistent.

Rockstar Puppy, an online company that sells pricey dog accessories through its website, advertises custom doghouses for as much as $20,000. Jessica Auria, who runs Rockstar Puppy, says she has sold a couple of them to celebrities, including one with heat and air-conditioning that can be controlled by an iPad.

Working with Barbara Thulin-Joyce, an interior designer, she created a doghouse for Jennifer Farley, better known to fans of "Jersey Shore" as JWoww. The doghouse, which they gave to Farley as a marketing promotion, is now advertised on the Rockstar Puppy website for $12,000, complete with matching hot-pink beds and miniature fabric drapes with jeweled pink tie-backs.

Both women seem to have high aspirations in the doghouse design world.

"I've got all kinds of really great ideas that I want to do for doghouses," said Thulin-Joyce, who runs a pet decor boutique called Decadent Digs.

Like?

"Music that comes on when the dog walks in," she said. "And windmills on top."