Rothfuss also does picture books. One, anyway: The Adventures of the Princess and Mr. Whiffle.
What is it about? I have no idea. The Princess and Mr. Whiffle, I suppose. The book has three endings, and I'm sure none of them are for children. Rothfuss even had a sticker made up for the book that says the book is not for children. I have to say, the caution that it isn't for children makes it all the more appealing to me.
There are a number of places you can buy a copy, but I recommend Pat's store. It's a little more costly than other places at $35.00, but all proceeds go to Heifer International, because Pat is a cool dude.