Too often, the world of digital learning resources is seen as black and white. On one side, there are professionally produced, expensive and closed textbooks, educational games, online course materials etc. On the other side is the heterogeneous universe of open educational resources, mostly produced by users (teachers, learners) themselves. Today, most of the textbook publishers are anxious about unavoidable digital turn in educational publishing business, as they fear to lose their profits. Yet, for the sake of the continuity and quality of digital content production in the educational domain, it is important to find the ways how both types can be integrated, remixed and re-used. We propose a didactically justified model for remixing and integrating proprietary digital educational content with user-generated open educational resources. We see the e-textbook of the future not as a fixed, uniform, static ePub, which is used as an input for the learning process. Rather we envisage it as a compilation produced by learners themselves as the main output of their studies, containing integrated pieces of three types: commercially produced content from publishers, resources developed by teachers, and, finally - the digital knowledge objects created by learner throughout the process of collaborative knowledge building.