Looks like the FOH sound is a blend of the Nobel and the BassRig + Cali 76. I don't see a mic on any of the cabs. Could also be pulling a DI off the SVT4.
The setup makes sense as he used to run SansAmps to do the same sorta thing.
Earlier in the tour he was running the Nobel and a Darkglass B7K + Harmonic Booster in the rack.
I've heard he had some crazy distortion from people that've seen them live, and the MXR Sub Octave Bass Fuzz makes sense.
All that said, Rex is known for doing product placements and openly admits it (note he skips the DCX Bass in his pedalboard demo), so I'm taking what I see with a grain of salt. I would like to know what's under the towel at 20:55. He's running a midi controller and rack switcher... with nothing to switch, and then there's this thing that looks about the size of a Quad Cortex hidden under a towel. Rex's tone isn't too difficult to nail, but I'd like to know what's going on behind the curtain.