We developed a Multi-Tenancy Framework for partners who want to realized multi-tenancy but 1) don’t want to make change on their current single tenant design, or 2) want to keep high level of isolation between tenants, so that to use local cache and allow per-tenant customization, which is only achievable in on-premise environment before. We originally developed this for two of our managed partners. Then, we decided to make it open source, so that everyone can benefit from it.
It is available now at http://cloudsamurai.codeplex.com/ . We just released v0.9 yesterday. Welcome to try and feedback.