Others had another explanation: ego.
"Each year it seems there are more extremely rich people with ever larger egos that have to be right on top of the mountainside . . . so everyone will know -- aha -- there is the richest person on the hill," said Joe Edmiston, director of the Santa Monica Mountains Conservancy, which has fought to preserve open space in the hillsides.
If there are 20 residences of 20,000-plus square feet in the works for Los Angeles County, it would represent a surge of mega-mansions. According to records from the Los Angeles County assessor, there are fewer than 60 homes with more than 20,000 square feet in the county and fewer than 10 with more than 30,000.
Still, real estate agents said assessor records aren't always accurate because they may not measure pool houses, cabanas and other similar living spaces.
Currently, many of the largest homes in the county are concentrated in the neighborhood of Beverly Park, a gated community in the hills south of Mulholland Drive in the city of Los Angeles; several houses there are at least 25,000 square feet.
The largest home in Los Angeles County remains the 50,000-plus-square-foot, 123-room Holmby Hills estate of the late Aaron Spelling, which has a bowling alley, doll museum and gift-wrapping room.
Kroh, who has filed plans for the house on top of the knoll with the city of Los Angeles, insisted that there is nothing remarkable about them.
Though paperwork on file with the city shows a house of 39,000 square feet, Kroh said it will actually be smaller. He also said he may not build the home after all.
Current plans call for two stories of 10,000 square feet each above ground, along with 12,000 square feet -- including a movie theater and an indoor pool -- below ground.
"I could find you hundreds of homes like that. Hundreds," Kroh said.
But even as plans are drawn for ever-larger homes, there is a growing chorus of people who are questioning the concept of the mega-mansion.
Spurred by complaints from homeowners that "mansionization" is ruining the character of many neighborhoods, the Los Angeles City Council last month approved new limits on the sizes of many Los Angeles houses.
The law applies only to the city's flatlands, but officials are working on a companion law for the city's hillsides, where many of these giant homes are slated to be built.
That is little comfort to homeowners who say an influx of giant homes has already hurt their neighborhoods.
