This paper details nano-scale devices being researched by physical scientists to build computational systems. It also reviews some existing system design work that uses the devices to be discussed. It concludes with a discussion of how the authors believe system-level research can best be used to positively affect actual device development. This work has led to a more thorough design methodology that will address whether or not computationally interesting and buildable circuits are possible with the Quantum-dot Cellular Automata (QCA), while also providing significant wins over end-of-the-roadmap CMOS.