Jerry Garcia's old house is just down the road from film meister George Lucas' big spread. The Mediterranean-style villa sits on 10.5 acres atop a hill that takes in sweeping views of the Marin County landscape.

The late guitarist for the Grateful Dead bought the house in 1992. The Deadhead dream house - which cost just over $1 million when it was custom-built six years ago - today it is on the market for $2,050,000.Garcia, who was one of the least materialistic stars around, probably wouldn't have cared about the dramatic run-up in the price of the luxury estate. But the increase is in keeping with the findings of a new report released Monday that tracked values of high-priced homes in California over the past 10 years.

Since 1985, the values of luxury homes have nearly doubled in the Bay Area - and are still rising, according to a study conducted by First Republic Bancorp Inc.

High-end homes jumped from an average price of $578,548 a decade ago to $1,131,634 at the end of June 1995, the bank reported. That's a 95.6 percent increase.

The study gives credence to the adage that - housing-wise and otherwise - the rich get richer.

Statistics from the California Association of Realtors show that the median price of a home in the Bay Area - more in keeping with what the rest of us buy - rose a comparative 77.1 percent during the past decade - to $256,990 from $145,130 in 1985.

The 10-year performance of "prestige" Bay Area homes - averaging out to an annual increase of 9.3 percent - was far superior to the 16 percent appreciation First Republic reported for Los Angeles and the 15 percent rise in San Diego over the same 10-year period.

Bay Area prices increased despite a statewide housing slump earlier this decade. As most homeowners know, residential values peaked in 1990, then declined for the next three years.

Values bounced back last year and have continued to rise during the first six months of this year, according to First Republic, and are not far off their 1990 highs.

"The declines of the early 1990s appear to be behind us," said Katherine August-deWilde, executive vice president of First Republic.

Of the prestige market, she said, "The limited supply of attractive homes in the most desirable communities, coupled with California's strengthening economy, has stabilized things.

"High-end homes in (the Bay Area) have been a good investment due to supply constraints and a diverse and vibrant economy," said August-deWilde.

There has been "considerable interest" in Garcia's home since the rock legend suffered a fatal heart attack Aug. 3, said Carla Himy, a Frank Howard Allen real estate agent who is selling the 7,500-square-foot mansion.

"The home was in perfect condition when he purchased it - and he made changes to it," Himy said. Wall-to-wall carpeting, for example, was taken out and replaced with a marble entryway and bird's eye maple floors - as well as some personal touches.

Garcia, who occupied the home only for about one year, was living in a new, custom-built home at the time of his death.

While luxury home prices have marched forward, Himy said she's also noticed a difference in the ages of buyers since nine years ago, when she first entered the business.

"People are a lot younger - in their late 30s and early 40s with young families," she said. "Maybe they don't have to borrow from mom and dad to consummate these deals in the million-plus price range. They have money in their own right."

Luxury home sales have been particularly strong on the Peninsula south of San Francisco, thanks to a boom in the high-tech industry and a fresh wave of buyers from Pacific Rim countries, according to real estate agents.

The communities of Woodside, Saratoga, Palo Alto and Atherton "have all been very, very strong," said August-deWilde. Values in those exclusive communities have benefited from nouveau riche entrepreneurs and executives from Silicon Valley.

In Hillsborough, "we're seeing an increase in interest from Pacific Rim buyers," said realty agent Ed Stephens, who specializes in the luxury home market in San Mateo County. "Recently, they've bought several large estates on the Peninsula."