(4) negotiate a deal where they get more then 30%.
(5) negotiate to remove DRM and operate as a Web App.
(6) change business models to subscription.
(7) license the app part of the business model to another company not involved with your store. That company can then pursue anti-trust claims against Apple if disallowed since they have no ability to offer the items for sale.
(8) add more value with your product i.e. get a better business model then "I'm gonna get rich being an additional middleman of ebooks"