I see books by file name, including .epub extension, when browsing the SD card. The folders need to be enabled, of course. I can't find the post that describes it, but I saved the text:
In the "System" dir on the SD-Card is a file "dr.ini", I added the line:
/apps/er/sys/ctb/showdir=sdcard
use wordpad for unix compatibility
Edit: Oops, seems they all show file names when sorted by title before they've been opened. Once you start reading the file name turns into the title. Sorry.