I think that the ebook should be publishable in multiple editions. For instance, my short story on Amazon, The Aristotelian, has a nice cover. But I would have preferred to include several illustrations inside. Yeah, maybe it would have a facsimile of my signature, or even a personalized message, but what would really be nice would be a number of beautiful illustrations of the English countryside, an embarrassed Holmes brother, dangling feet of the body hanging in the locked room, and so on.
ebooks enable the production of "coffee table" editions that can be as richly illustrated as a web page. In a perfect world, I'd like to sell a Kindle ebook edition at $0.99, a richly illustrated edition for more, another edition with personalized message for more, and a paper version printed on glossy stock with hardback covers for an even higher price.