Exploitation of silicon capacity will require improvements in design productivity and more scalable system paradigms. Asynchronous message passing networks on chip (NOC) have been proposed as backbones for billion-transistor ASICs. We present a novel layered backbone-platform-system (BPS) design methodology for development of network-on-chip based products. It combines and extends the distributed, parallel, embedded and platform-based design concepts in order to manage the diversity and complexity of NOC-based systems. The reuse of communication principles in various platforms, the reuse of platforms in product differentiation, and system-level decision-support methods are the cornerstones of our methodology. The presented mappability estimation and workload simulations demonstrate the feasibility of such methods.