I've thought about this before as a physical item. Like maybe a breadbox size ePaper screen that looks like a tiny bookcase with a API back to Goodreads or something to get the book spine images.
You could also have a section that displays random quotes from books in your library.
Unfortunately for now the licensing on color ePaper is still prohibitive and doing it with an lcd seems somehow tacky to me.
I've also had a similar, but slightly different idea for a practical desktop display - get it to show nice tidbits like a wallpaper. For example, a Newton's cradle, or a spinning top, or a lava lamp or whatever folks put on their desks. Though coding it would be a bit of a challenge for a non-CS guy like me.
You could also have a section that displays random quotes from books in your library.
Unfortunately for now the licensing on color ePaper is still prohibitive and doing it with an lcd seems somehow tacky to me.