In recent years, a variety of initiatives have been funded with the aim of producing software tools or environments of a type variously known as virtual research environments, research infrastructures, or cyberinfrastructures. These initiatives vary in their scale, specialization, scope, and level of funding. One issue that they face in common, however, is that of sustainability: how can the continued--and useful--existence of a system or tool be guaranteed, or at least facilitated, once a project's funding has been spent? In this paper, we examine how such sustainability has been enabled, in the particular case of infrastructures for textual scholarship, in the context of three international projects: TextGrid,1 TEXTvre,2 and DARIAH3. Firstly, we will address the inter-project collaboration and crossfertilization between TextGrid and TEXTvre, including architectural decisions and shared data infrastructures, and investigate how the projects benefited from the exchange. We will then discuss how this existing collaboration can be taken forward by the loosely-coupled and distributed framework being developed by the DARIAH community, and how it can serve as a model for the sort of collaborations that DARIAH plans to enable.