According to a profile in Architectural Digest, Nate Ruess is currently writing a Broadway musical:
Ruess, who is currently writing a Broadway musical, frames the success of the project in terms of the apartment’s mood rather than the individual elements that create it. “The loft is civilized and comfortable. It’s not about a flashy moment or a photo op. It’s about real life—our life,” he says. Ronson adds, “Nothing feels overly modern or heavily traditional. The look is simply classic.”
Also, the basis of the article, his family’s home, is a pretty incredible sight.