Rumors are again swirling that Anna Wintour could be tapped for the diplomatic post of US ambassador to London, replacing Louis Susman, who is to retire this year. The Vogue editor is a top bundler for President Obama and is attending fund-raisers this week in Chicago and New York, but we’re told she isn’t quite jumping at the chance to grace the grand but not terribly fashionable US Embassy in Grosvenor Square. A source said, “These are just rumors. She’s quite happy at her current job.”