JOST is a audio host application for plugins that can be used as plugin itself, 
or be compiled as a cross bridge between multiple audio plugin technologies...
It is the first open source multi-technology (internal, native vst, ladspa,
dssi) host in linux. It will mainly host a chain of plugins per instance,
publishing jack, alsa, and alsa_seq ports in order to be connected in your main
stream flow. It is actually under heavy development, but it still has some
very good features that make it a first class host.  

This requires jack-audio-connection-kit (runtime only).