ML runs on dual digic cameras with g3gg0's hack finally but it's still on testing phase. Just wait a moment and you'll find ML running in 7D and 1DX.
Imho the moment will take several month because the dev focus is the 5d3 at the moment, and that'll be some time because there seem to be some unexpected regressions w/ the new digic5 cpu. And for ml to run on the 1dx you'll have to donate or lend one to the devs :->hmm I did feel the camera getting hot, I was thinking it was just because I was doing video, although it did seem perhaps a bit hot for so little time, not sure though hmm
Peaking is one of more cpu-intensive things to do (depends on the algorithm you select in the menu), so as w/ running video you might feel the camera getting warmer. But it's been tried so many times by so many people there's really no reason to worry.
I believe Alex is doing the 5D3 but g3gg0 is doing most of the work for 7D. As for 1DX, I think somebody will lend it eventually. I don't know but I get the feeling that the 1DX hack will include making it into a 1DC. If this is a probability, some guys in the movie industry will certainly sponsor this.