Keystone is a cross-platform, object oriented application framework which allows applications to be written to build on the target platforms of GNU/Linux and Win32 without modification of their source. Keystone implements several modern Web standards, including SVG graphics and the XUL user interface description language.
COID is an object-oriented networking library with a tool that automatically generates a lightweight communication layer directly from a C++ class declaration. The coidgen tool automatically extracts designated classes and methods from specified header files and generates a corresponding client class and host dispatcher. The server library manages networked and local connections and provides various services to running objects. The communication layer establishes either remote connection through TCP or direct (vtable) connection between the client and the server (if they reside in the same process).
QoS Enabled Distributed Objects implements a CCM and adds some more advanced features such as QoS extensions and interoperability with other middleware technologies. Please note that you also need the generator for implementing your own components, and it can be found at the same place.
OpenCCM (Open CORBA Component Model) is an implementation of the CORBA Component Model (CCM) specification defined by the Object Management Group (OMG). The CCM is the first vendor neutral open standard for distributed component computing, supporting various programming languages, operating systems, networks, CORBA products, and vendors seamlessly. The CCM is the OMG's specification for creating distributed, server-side scalable, component-based, language-neutral, transactional, multi-user, secure applications. One CCM application can be deployed and run on several distributed nodes simultaneously.
The Interreality project is a collection of Open Source, Free Software projects based on the Virtual Object System (VOS) platform. The goal is to develop a free and open platform for multi-user 3D virtual reality games, applications, and interactive, collaborative 3D virtual spaces. VOS is a powerful and generic network object framework designed to support a variety of high-performance applications. It is the basis for Ter'Angreal, a general-purpose browser application for entering and participating in 3D worlds.
XPLC is a component system that tries to enable the use of components in a pervasive way. It aims to be easy to use, have low speed and size overhead, and be language and platform neutral. Basically, the idea is to leave no excuse for an application not to be component-enabled (being a component and/or using components).