Secret camoflauge endpage pocket
I created this hardcover journal as a custom commission for someone traveling on their bicycle from North to South America - the specs were:
map of south America on the cover
I added an awesome camouflaged secret pocket for storing important documents or extra cash.
Interestingly, when I inquired what colors they might like to have in their books they replied "it doesn't matter" - I asked, "really, no preference?" and it was revealed that the entire family is color blind and the only colors that appear true are shades of blue.
In response I avoided red and green bookcloth and chose a nice brown silk Japanese cloth - I also chose a high contrast geometric endpaper so that hopefully it will still look cool even if the colors are different from the way they appear to me.