I wrote a paper with my old coworker and friend Joseph Anderson on reverb architectures for Ambisonics. You can download the paper here.
It was a lot of fun writing a paper with Dr. Anderson, who is also a master of writing compositions that use Ambisonics to nice effect. Joe (ok, I call him Joe) manages to make Ambisonics work beautifully. One of his compositions uses a salad bowl spinning around a SoundField microphone, which is a very expensive way of getting a simple effect, but the results are stunning when heard in an Ambisonics environment.
One of my reverb diagrams got mangled when the paper was converted to PDF, so here it is in higher definition (click on the image to see it in more detail):
The Halls of Valhalla 