Looks great! I agree cables are not as intimidating as people tend to think - my first ever knitting project was a sweater with a huge cable down the front! Glad I hadn't heard that cables were supposed to be hard - probably never would have tried that!
That's awesome, and a great way to put all the books together - you don't get to see all the artwork on the covers, but that is a mroe do-able necklace than hanging them all separately on a chain! May have to try making stacks, myself!