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.
From what I see in the mercurial logs, g3gg0 does the low-level stuff, but other people (mainly alex) do the programing. And did I mention I personally added focus bracketing to the current ml trunk :-) ... it's great programing your camera, that's why I don't want to switch to Nikon.
Concerning 1dx/1dc: If someone really hacks the 1dx and backports the 1dc firmware, ml imho will be in real trouble because Canon will change the "ignore" policy to "hostile". So I could do w/o 1dc features on the 1dx, I cannot afford one anyway. Magic Lantern is a community project to beef up low- to midrange dlsr, not saving money for rich people.