I've been eying the Tritton surround sound headsets for gaming
for their audio controller. Over the weekend I found a guy
selling just the controllers on Ebay. The AX360 has coaxial and
optical in:  The AX Pro only has optical in, maybe other
differences too:  Hopefully I'll get them soon, I ordered one to
use in my home Z5500's to replace the pod, and the other to get
5.1 when I get around to building my car PC.  I'll post up how
it works when I get it and hook up my home speakers.