Multi-instrumental musicianship appears in various musical traditions, also frequently figuring in systems of music teacher education. Multi-instrumentalism covers forms of musical creativity and versatile professionalism that differ from ideologies of specialization often emphasized in instrumental music education. Thus, it is relevant to ask whether and how multi-instrumentalism might also shape music teacher identities. This question was explored through a case study of three experienced multi-instrumental teachers in the Swedish system of Schools of Music and Performing Arts -- exemplifying a context in which teachers have large freedom to shape their work. Teacher narratives were analyzed with reference to the binary oppositions between versatility versus specialization and musician versus teacher. The results show that multi-instrumentalist teachers may not only occupy subject positions as versatile "all-round musicians," but that they may also carve their identities as specialized "performers," or adopt teacher-focused identities such as "gamemaster," "coach," or "counselor." Furthermore, for some teachers, the shifts between instruments may themselves involve shifts between such subject positions. Based on our findings, multi-instrumentalism appears as a potent teacher resource within educational systems which are extensively driven by students' needs and interests.