I really agree with what Toadhead said. I think that you would have to purchase the bigger bags and wallets( or find them). The more storage space that an item had, the more expensive it would be. And what Black_Rose said about the money bags gettin bigger when you put more money in them. I dont however agree with the pictures thing, i dunno why but i thought that was kind of lame (no offense, im sure it could work out to be great).
I think that haveing bags and backpacks would be a great idea, and add to the realism of the game, because no one can carry four armors and 3 shields.