When comedian Bob Hope's house was fist built in Palm Springs, Calif., in 1973 at a cost of $3 million, the mushroom-shaped roof alone reportedly cost $654,000.

Destroyed by fire before the Hopes moved in, the house is now rebuilt. Or almost rebuilt.

Dolores Hope, giving a group of rich Republican friends a guided tour, giggled over the fact that the glass dome still hasn't been replaced, leaving the main part of the house exposed to the sky and the elements.

Escalating construction costs have made the roof "too expensive," she said, adding: "We may freeze to death on the way from the bedrooms to the kitchen."

The house, which Hope once boasted was large enough to "hold next year's Super Bowl," reportedly contains some 29,000 square feet of floor space and was patterned after the Trans World Airlines terminal in New York.

One Hope friend who has seen the house says that Dolores Hope discovered there were rooms she didn't even know she had until the architect's drawings were actually translated into space she could walk through.

One of the "dividend" rooms has been made into a small, private religious chapel.

A "dirty tricks" burglary in Plains, Ga.?

While "Miss Lillian" Carter was visiting Cairo, someone broke into her house.

The sheriff's office is being so non-committal that Miss Lillian's neighbors are atwitter with speculation about what the thieves were after.

A Carter family spokesman says that no one will know for certain if anything was stolen until Miss Lillian gets back and takes inventory.

There are Secret Service agents stationed at the president's house in Plains, but his mother didn't want them around her. She preferred to be guarded by a former Georgia state policeman. But she took him with her to Egypt and left no one behind at the house.

Speakers invited to address the State Department's noontime open forum can usually expect an audience of 50 or 60 career foreign service officers. But it was standing-room only, with people spilling out into the halls, when Richard Allen -- who is being touted as Ronald Reagan's choice for secretary of state -- showed up to discuss "The Theory and Practice of House-Cleaning, or How To Survive A Reagan Administration." He has since been besieged with phone calls, resumes and letters typed on State Department letterhead. . . .

At the Children's Museum benefit on Saturday night, a woman brazenly sidled up to former child star Margaret O'Brien and wanted to know if the price of her ticket gave her the right to ask how old O'Brien is now. O'Brien cooly refused to tell her. . . .

In Washington, where almost everyone seems to write his memoirs eventually, friends and relatives who lived through the same events frequently respond: "That's not how I remember it . . ." Columnist Art Buchwald got to insert his dissenting recollections into his wife Ann's new book, "Seems Like Yesterday," an account of their life in Paris which is being published by Putnam. . . .

A college girl who worked at I. Magnin's in Los Angeles over Christmas says that Nancy Reagan has a reputation with the sales clerks for being so thrifty that she returns all gifts -- even boxes of chocolates -- and takes credit on her charge account instead. . . .

It will come as a surprise that Jacqueline Kennedy Onassis ever heard of the word "budget." But she had one on the new house she is building on Martha's Vineyard, according to architect Hugh Newell Jacobsen, who is telling friends proudly that he brought in the contractng bids under the amount she allowed him to spend.