Had a great conversation with Erik Olsen of SigBlips.com, creator of baudline. Eick expressed an interest in the integration of VisualHearing with baudline. He also pointed out xgl and the Kororaa live cd. The xgl desktop allowes you to set the transperancy on each window. This seems like a great way to overlay different visualizations.
Here is an archetecture that may work with this in mind.