In this talk, we will describe a plan for the development of a wide-area testbed for the Tor anonymity system. Our proposed testbed would have the ability to directly run real-world software for anonymous communication, including support for clients, relays, and other critical components of Tor, such as directory services and bandwidth authorities. Researchers could select the experimental parameters, including user models, upload modified versions of Tor and associated scripts, and run an instance for a period of time. In the rest of this talk abstract, we lay out the motivations for having a testbed, the characteristics and use cases we anticipate, and the goals for the HotPETs talk.