Replying just to bookmark this in case someone answers!
I wonder if the virtual orchestra people are seeing something that makes sense here? I thought so much of the architecture was geared to video work that you'd be paying for pci throughput performance you'd never touch with audio.
Still running my 2009/2010 Mac Pro (2.93 - 3.33GHz 8 core i7) and my 2011 Macbook Pro (2.5 - 3.6GHz 4 core i7). The Mac Pro is still overpowered for everything I do from studio to live sound. The MBP is a little beast too.
I have to admit that new Mac Pro looks for all the world like the Jobs era quality of build. That price tag... Nothing else post-Jobs seems like Apple quality anymore.