I have only recently got the cupcake book and made the sharks for a class party at my son's school. I don't think we can get twinkies here in Australia so I used sponge fingers. They're hard and you usually use them in things like trifle or tiramisu where you can soak them softer with juice, coffee or liquer. They worked really well.
I have come here today to kick ass and chew bubblegum...and I'm all outta bubblegum!