Guilherme Martins has made a printable paper version of the Arduino board. This amazing project allows you to download the PDF file, print out the top and bottom layout, glue them to whatever support you like and start adding components. The PDF files, a list of the necessary electronic components and instructions are all available at Guilherme’s site here..
Perhaps it might be asking a little too much of your readers to ask them to build an Arduino board before they can read your book but I find the concept of printed and shareable electronics fascinating. Arduino boards are powerful pieces of electronics capable of a great variety of control tasks, but what if you printed simpler circuits onto paper for people to download and connect up. I imagine some of the circuitry that controls the Electronic Popables might be suitable for this kind of project.
Of course, if you also have a printer that’s able to print in conductive ink then you would save yourself a lot of time..