We describe a design for a collaborative Virtual Learning Environment (VLE) to support massively multi-user and multi-institutional learning communities. This architecture extends Croquet to encompass a tier of distributed cache servers that allow intelligent caching and pre-fetching of objects, scene definitions, and textures. The design also provides for Interactivity servers tied to specific regions in the VLE. Interactivity servers provide persistence for neighborhoods, coordinate modification and transient phenomena for locales in the virtual space, and ensure trust relations by managing user identification, authentication, and authorization via integration with existing institutional authentication infrastructure. This system supports real-time interactions that promote a self-organizing, interdisciplinary knowledge sharing system within a scalable VLE in a manner that ensures accountability and trust relations.