P.S.
Gotta say though, now that I've figured out how to add my Dropbox account to KOReader, the OPDS probably won't get used much.
On the plus side, I'm getting more use out of my Kindle now. Transferring EPUB files to the Kindle via Dropbox is super easy and all I need is my smartphone. No need to go through desktop+Calibre to convert to MOBI/KF8. I can just read the EPUB immediately.
KOReader Rocks!