In this paper we will report from an on-going EU-financed project aiming at developing innovative cross-border, virtual classroom instructional designs; that is designs where classes from three Nordic countries collaborate by means of technology to enhance teaching and learning. School management, teachers, students, and educational researchers from Denmark, Norway and Sweden collaborate since 2011 in three-country teams on all levels to explore and evaluate novel cross-border instructional designs in four subjects. The research approach is user-driven innovation by means of Action Research and Design-based research. The cross- border instructional designs exhibit several challenges: designs need to be aligned with all national curriculums with respect to 1) subject content and 2) learning goals, and in order to advance learning, we need to address 3) learning benefits due to the collaboration. In Mathematics, such cross-border learning benefits were particular elusive to identify, so some kind of guidance were needed. The model, first proposed for Mathematics but generalizable to other subjects, is a three-dimensional cube that categorizes an instructional design with respect to 1) subject-content, 2) aimed-for competence, and 3) learning-benefit. The subject contents and required competencies were derived and synthesized from the national curricula, whereas the learning benefits were inspired from previous cross-border designs. The model has successfully been used as a classification system for virtual classroom tasks, and also as an innovation tool to generate novel instructional designs where the expected learning benefits became explicit from start, which facilitates design evaluation.