I remember two: Julie Chen showed her exquisitely printed book, Invented Landscape, and
Alice Austin displayed an original work as well.
Here is a model of the structure. It is a variation (yes, I always have to mess with it), made with a circle accordion (MHB, 119) and gessoed panels that stick out when the book is closed. I like that this book has the potential for two interwoven stories, possibly about pivotal moments; you can flip the panels discreetly without completely turning over the book. Hedi's version, it should be noted, closes with all panels hidden inside, protected.
I'll be teaching a class on how to make the structure this June. Watch the class listings for further information.
You might try this creative process exercise before making a pivoting panel book: think about a pivotal moment such as when you had a sudden realization or when an outside event changed your life. Maybe it was meeting someone, finding something or someone you thought you'd lost, a natural or historical event, or some kind of a coincidence. Then think about the life of that thing or person before the change. Write two parallel pieces from different points of view or create two strikingly different visual pieces.
Attending the bookfair always provides a pivotal moment for me. This time it was getting to examine a new book structure.
Watch the Codex Foundation page for the next event in 2013.