It used to be that a limestone between Fifth and Madison was the ultimate sign of wealth and privilege. No longer. The Andrew Carnegie–style dwellings of the past have been replaced in status by having several limestone townhouses in a row. A handful of such architectural concoctions have made headlines recently for their sheer grandiosity (Sarah Jessica Parker’s twin townhouses span 50 feet) and somewhat bizarre, cobbled-together appearance (Russian oligarch Roman Abramovich’s two Queen Annes and one Federal brick townhouse).
For these celebrities and megarich people, Greenwich won’t do. “They want to be in the city,” says appraiser Jonathan Miller. But in order to get as much space as they would in the suburbs, these billionaires need to get creative — whether by connecting a loft to a carriage house to a loft next door or, as is the trend in London, by digging several floors down to create what are essentially basement penthouses. […]