@Deicide:
Me too. The bag has some purpose. Maybe it's just to allow a funny gag to happen later, but Oda probably included it for some reason.
It's like Franky's nunchakus in Thriller Bark. Everyone was guessing what the hell was Franky carrying with him back then.
That doesn't mean there's a character inside, though.
Aye..I was all set and gave up, now a small part of me is still holding out hope, though I know it's not gonna happen.
I didn't even know the bag and cloak was there until you brought it up.
If anything, what I think is gonna happen, is that Luffy will lose the cloak, and we'll go a quick panel of him saying goodbye to Hancock..