Pressures on mobile network operators to support ever increasing data rates, while keeping costs fairly flat, will require large scale and dynamic sharing of resources among operators, as well as harnessing of spontaneously deployed local area wireless infrastructure. We have recently proposed the concept of Networks without Borders, which allow for the dynamic establishment of virtual networks from a pool of wireless resources, encompassing spectrum, infrastructure, and management and control functionality. In this talk, we will present our initial models for the sharing of infrastructure and spectrum and its impact on coverage and aggregate capacity. We employ game theory to model the use of carrier aggregation and the ability of mobile network operators to schedule access to each other’s licensed spectrum. On the infrastructure side, we have started to use mobile operator data from Europe to quantify the infrastructure requirements to achieve a given coverage target, treating current base station deployment as a pool of resources from which a virtual network can be architected.