Tell me if you have any problems with the DXF file (though it is a standard format that should be readable by any designer using any OS), I can export it to PDF.

Speakin as a designer, I'd like to quote Antoine de Saint-Exupéry: Perfection in design is not achieved when there is nothing more to add, but when there is nothing more to remove.

At least for the book version, I would like to see something really simple, along the lines of the flip cover for the Palm: