I share your love of the format! I am seeing some books in the consciousness/philosophy space using it -- for example, Eric Wargo's Becoming Timefaring. Also The Dark Forest Anthology of the Internet. Print on Demand allows for the dimension to come back without the need for massive sales. I love the format precisely because it fits in my back pocket and allows me to take a walk in the park on on the train without needing my dang man bag. Also, I will soon be publishing the second edition of Lucid Talisman in a similar pocket-able size 4.25 x 7 (same width, slightly taller).