Can't think of any devices I've used for it that were weird in the sense of not intended to be used for books - tho I briefly tested a book reader on my GBA, I never actually read a book on it.
A device that was intended for reading books, but is still relatively weird/unusual, was my old phone, the Yotaphone 2. A Russian design (tho also got manufactured in China, like most things), it was an Android phone with a regular 5" AMOLED screen on the front for general phone/Android use, but a second screen on the back which was e-paper for reading books. It was a pretty decent phone at the time and the gimmick worked well.