Still no word on what it's called, what it's about, when we'll see it, or if it has even been written yet, but the New York Observer has a small interview with Charlie's editor at Grand Central, Ben Greenberg.

"I've been chasing after Charlie for years," Mr. Greenberg told The Observer. "Without ever having spoken to him. It was just an idea."

Grand Central snagged the novel in a pre-empt, after exclusive negotiations. (Mr. Kaufman is represented by Claudia Ballard at William Morris Endeavor, which also represents his screen work.)

[...] "It was just something that he wasn't going to do until he wanted to do it," he said. (Elliptical! Not unlike a Kaufman screenplay.) (Source)