The most expensive single-family home listed in MLS in San Francisco is this 11,455 sq foot house in Pacific Heights—listed for $29,950,000 and featuring, "...nine bedrooms, nine-plus baths, airy central courtyard, attached garage, sauna, wine cellar, fireplaces, and unobstructed, panoramic views of Golden Gate Bridge and the San Francisco Bay."
You'd think they'd post more pictures.
According to this Wave magazine article (not sure of the date), it was originally listed at $45 million, though, so maybe that's not bad. (Who says the San Francisco home market hasn't gone down?)
Larry Ellison could be your neighbor.
Probably drafty.