Ive read through every thread w the word audiobook in it, and i can't find an answer to this. I know when you guys started u were mainly concerned w just competing w xbmc in the 10ft display market, but after building out incredibly functional and beautiful ui's for nearly every platform out there, what is stopping you from forgetting about xbmc and competing w itunes/amazon/google/etc. Seamless cloud storage and playback of large video files is still YEARS away, and in the mean time the absolute best media management solution i can imagine is a home server/nas/etc (you could even kickstart a hardware branch of plex and start selling "plex servers" that are streamlined for media storage and transcoding) that would store ALL a family's media (Music, Movies, TV Shows, Music Videos, Books, Audiobooks, Podcasts, Magazines, Comics, and Pictures). And then any device under the sun could stream from there.
I think books and audiobooks especially can benefit immensely from this kind of setup. You guys could setup a method of storing the corresponding book/audiobook in the same folder (like metadata) and create a whispersync situation where someone could seamlessly transition from written word to audio. This is obviously a more ambitious feature request, but i think something as simple as a dedicated Category, and UI made specifically for audiobooks (15 second rewind, save pause states, FF, etc) or music videos (treated like music NOT videos) would go a LONG way