It has been shown that large robots can be safely installed for human-robot collaborative assembly cells in experimental setups. It has also been found that these installations require demanding considerations of a significant number of layout and safety parameters. This indicates that successful commercial implementations will require a resource efficient model for production system design that anticipates utilization of large robots in collaborative settings. Experiences from experimental setups have been used to explore a basic model for such production system design, to stimulate a discussion regarding what model characteristics should be tested and validated in future research.