Industrial Cyber-Physical Systems (CPS) are complex heterogeneous and distributed computing systems, typically integrating and interconnecting a large number of subsystems and containing a substantial number of hardware and software components. Producers of these distributed Cyber-Physical Systems (dCPS) face serious challenges with respect to designing the next generations of these machines and require proper support in making (early) design decisions to avoid expensive and time consuming oversights. This calls for efficient and scalable systemlevel Design Space Exploration (DSE) methods for dCPS.In this position paper, we review the current state of the art in DSE, and argue that efficient and scalable DSE technology for dCPS is more or less non-existing and constitutes a largely unchartered research area. Moreover, we identify several research challenges that need to be addressed and discuss possible directions for targeting such DSE technology for dCPS.