One of the most requested features on the Bible.is iPhone forum is to have local audio files and I propose that Android users have the same request (I know I do!).  I understand that the download size is a major issue.  A few suggestions to overcome that could be to [1] download to PC and install via USB link or [2] provide audio pre-loaded on a micoSD card and insert directly into phone.  Just a consideration - the SD card option would need to be large enough to still have plenty of room for all of the other apps and files that an average smartphone user would typically have.