Might be time to reconsider. Canon are (supposedly) not planning any further flagship DSLRs and I see little wrong with modifying your own property.

Independent of that: how dangerous is ML dev to the cameras themselves (in terms of brick potential)? Permanently bricking a camera in the price range of the 1DX is not exactly my idea of a good time. :-)

Over the years, a few devs have temp soft bricked cams, requiring various non-standard methods to restore them to working order. I think all attempts succeeded so far! I don't think any permanent physical damage has been triggered by devs. It is definitely a real risk, but we try to work with the OS when possible, and the OS was written to try to make these things hard.

I don't think I'd want to learn the ropes on a cam too expensive to psychologically say goodbye to. Maybe save that for the second port.