As for the arc has reached 20 chapters and the release of vol. 46, I guess it's time to speculate what will come in the next volume.
My prediction that the volume will go until chapter 460, which has a good cliffhanger, and the title will be "General Zombie Night". In the cover I guess it will feature mainly Moria, Tallaran, probably Ryuma and Jigoroh, and Luffy wearing an armor. Maybe Perona, Absalom and Hogback will show up too, but not sure.
Post your ideas and predictions too!
http://apforums.net/showpost.php?p=626924&postcount=209 (SBS break down by Greg)
USOPP GALLERY PIRATES
http://apforums.net/showpost.php?p=629333&postcount=289
Vol. 47 SBS:
(Thanks to 99 @ JoJoHot)