As we're talking about future products, we might as well use the Thunderbolt I/O technology.
This should be implemented in the MFC-101 in addition to the new Ultra on steroids.
But why does everybody only mention MIDI, when talking about USB?
More importantly, with a USB or Thunderbolt connection, the Axe-Fx could also serve as a high quality audio interface.
To take Axe-Fx to the nest level - Fractal Audio need to develop plug-ins for DAWs - and integrate it with the hardware unit (Axe-Fx) that we all love so much. Taking it far beyond the Avid Eleven Rack (which is a 8 in 2 out audio interface (Pro Tools) in addition to being a guitar processor).
Just for fun, I bought a Fender G-Dec 30, mainly to use for practice. I connected the thing (USB) to my MacBook Pro and immediately started to edit the presets - easy and cool. Then I started up Pro Tools 9, and used the Fender as an audio interface, actually hearing my Pro Tools projects thru the speaker of the G-Dec 30. Nothing else needed! Total mix and click thru G-Dec speaker, while recording guitar sounds from G-Dec into Pro Tools, easy!.
Depending on what is inside the Axe-Fx unit (hardware), the future Axe-Fx might need to be a hardware plug-in for DAWs. I'm not sure if Fractal could reproduce the Axe-Fx in a plug-in, or how much computing power is needed. Again the Tunderbolt connection would be the way to go!
The Thunderbolt could easily pass audio signals, MIDI stuff, and everything else in a daisy chain: Computer - Axe-Fx - Controller (MFC-101)
Anything else, perhaps future guitars, could be added to the chain.