Mark Zuckerberg has already won the race to become San Francisco's most obnoxious techie homeowner. But a report says another Noe Valley manse owned by a "tech couple" could surpass Fort Zuckerberg as the most expensive property in the neighborhood.

According to the San Francisco real estate blog SocketSite, an anonymous tech duo laid down $7 million for a 6,000-square-foot home earlier this year. That purchase alone "became the most expensive home to have ever traded hands in Noe Valley."

Since then, they've gobbled up nearby property to protect their seven million dollar view—and they're spending millions more to build an "underground bunker:"

Hidden behind an LLC, the couple has also quietly acquired the adjacent undeveloped parcel to the west (645 Duncan), a parcel upon which a 5,000-square-foot home was approved to rise and sparked a rather ironic fight to preserve "the character and charm" of Noe Valley.

Instead of building a four-story home on the lot, a development which would block the views from their home at 625 Duncan, the couple is working on plans to build a modern underground bunker on the parcel, an effective 800-square-foot addition to their home next door. The parcel will then be landscaped as a garden and playground for 625 Duncan, "with switchback paths and patios that terminate at the top of the property at a huge view deck…and lots of lounge chairs at every level," according to a plugged-in source.

When the renovations and expansions are complete, SocketSite estimates the property could become the area's "first eight-figure [...] estate."

So which "tech couple" plans to ride out San Francisco's class war in a stylish subterranean sanctuary? The usually gossip-heavy SocketSite doesn't drop any specifics, but we asked around and made a few educated guesses: Kevin and Julia Hartz (co-founders of Eventbrite), Ruchi and Aditya Agarwal (Facebook, Cove, Dropbox), and Kevin and Elizabeth Weil (Twitter, Andreessen Horowitz).

Know who it is for sure (or have a guess of your own)? Drop it in the comments, or email us at tips@valleywag.com.