I asked about this a while back as well. It would really be great if we could choose the default file saving/naming options for Audible files like we can for normal CD rips (i.e. base path, plus folder and file naming conventions.) At the moment, every time I download Audible content I immediately have to move it manually.
I know that Audible files "can" be moved -- it's a matter of having MC do it automatically like it does with other types of content. This seems like a logical capability for MC to offer given it's robust approach to Media handling. I don't like having ALL my audible content in one giant folder -- I use the "Artist/Album" structure with "Artist" being the "Author" and "Album" being the "Book," "Periodical Series," or "Performance."
Thanks for considering this,
Larry
PS. As of the last time I checked, MC still had a problem with the Portable Device module thinking that Audible files were "missing" if they were moved while the iPod was connected. Doing a "Recheck Sync" did not solve the issue -- the iPod had to be ejected/reconnected, or MC had to be shut down and re-launched in order for the sync to work.