The Net::Clacks system implements a fast client/server based interprocess messaging. For handling a high number of clients, you can run multiple servers in a master/slave configuration. A slave can also run itself as master for it's own slaves, so a tree-like setup is possible.
Clacks has two ways to handle data. One is (near) real time messaging, the other is storing in memory (as a replacement for memcached).
Clacks has also a DEBUG feature, that forwards all messages to a requesting client.