Rob Lowe, media kingpin? The actor and Colony Capital chief executive Tom Barrack are creating a multimedia venture backed with $500 million. The new company will have a portfolio within California-based Colony to invest in sports teams, distribution firms, television networks or online properties. “It’s pretty far along,” said a source close to the deal. Reps for Lowe and Barrack, who helped Annie Leibovitz restructure her debt this year, had no comment. On Tuesday, Lowe and Barrack were spotted at dinner in London with Flavio Briatore, Guiseppe Cipriani and David Blaine at the C London restaurant to discuss the deal.