Physical Audio has released Derailer Quad, a version of Derailer specifically for use with 4-channel audio systems. Each resonator has its left and right output assigned to pairs of channels, along with a freely assignable driver signal. This gives an immersive sound environment, placing you at the heart of the physical modelling network.
Setup details for hosts such as Logic Pro and Ableton Live can be found in this blog post.
Derailer Quad uses the standard Derailer licence, currently $179.