First light 
This is the io voltage (VREF_VOUT) at 5V from the outside (VOUT):
And this is what happens at 30V from the outside:
No fire or smoke, just the mosfets switching off as they should.
This is with the most basic way of wiring up the circuit. I left out all the extra provisions for stronger hysteresis and so on.
There are many more tests to do in the next few days, but this looks promising.