Roberto Giobbi's book Confidences fits the bill. It's small and really easy to read. I wrote a review here:
sutra449815.phpSome others I've really enjoyed which meet the criteria:
Woody Aragon's A Book In English
Ramon Roiboo's Thinking The Impossible
Mayhew by John Lovick (Although the sarcastic subtitle "What Women Want" might make it a bit embarrassing to read on the beach!)
John Guastaferro's One Degree
And you've probably already read this but just in case: John Bannon's Dear Mr Fantasy
For me, the most important criteria for a holiday book is that it feels conversational... Like you are sat on the beach having a chat with the author. All of the above felt that way to me. And they all also contain really incredible magic.
Let us know what you decide to go with and if it turns out to be good.
Cheers,
Sam