I just noticed this project at Apache OpenCMIS:
https://svn.apache.org/repos/asf/chemistry/opencmis/trunk/chemistry-opencmis-bridge
There is no description, no documentation, and reading the code does not give many hints about what it is supposed to do.
Apache OpenCMIS sometimes releases great software silently, with little communication, so we might be missing another great piece of software here.
A Google Search for "OpenCMIS Bridge" returns only source code and the bare download page.
The OpenCMIS Bridge works like a proxy server. It accepts CMIS requests and forwards them to a CMIS server. On the way it can change the binding, and filter, enrich and federate data.
Here are few use cases:
The OpenCMIS Bridge is only a framework, though. It just provides the infrastructure and the hooks to add your own code and rules. If you are looking for a real world application, check SAP Document Center (formerly "SAP Mobile Documents"). It is based on the OpenCMIS Bridge.