One of the popular site for purchase of downloadable audio books is audible.com. I recently purchased a first book from them which was supposed to be in mp3 format; after download I found out that it is in a protected version of mp3 and does not play on any of my squeezeboxes. I contacted audible.com support and was informed that playing these files (*.aa ??) with squeezebox would require a firmware change that Logitech would have to make. Just for info: Sonos has made this firmware adjustment and these files play well on the Sonos system. If you consider such a firmware adjustment you might also consider addition of a bookmark because nobody would listen to a 17 hr audiobook 'in a string' but portions at a time. Perhaps, Logitech Audio could work with audible.com to implement the ability to play their audio book files on the squeezebox. That would certainly be a welcome development for a segment of your customers; and it would keep the squeezebox in step with Sonos.
Thanks for consideration.