Ever-busy James Franco is teaming with the team behind hot Sundance documentary “The Imposter.” We hear the “Oz: The Great and Powerful” star — also known as a grad student, artist and Playboy columnist — met director Bart Layton and producer Dimitri Doganis after seeing their real-life psychological thriller at the Utah festival, and is now developing a “hybrid” doc feature with the UK-based pair. “Imposter” follows a French-Algerian con man who contacts a stunned San Antonio, Texas, family to say he’s a relative who mysteriously disappeared years before as a teen. Franco’s project with the filmmakers will be “based on a true story almost as unusual as ‘The Imposter,’ ” a source tells Page Six.