I''m interested in this too.
I'm thinking of going for a Mac Pro this year, which only has 4 USB3 ports.
I've used my Virus as sound-card and synth for live sets on my 2011 MacBook 13".
So, I'm thinking either:
1) Dock with more USB ports (like the Belkin)
2) audio streamers like the Virus connected to 3 ports on the Mac and a hub for less time-critical devices.
Any thoughts or suggestions welcome.