So, while it's definitely a low-hanging fruit with high rewards, I don't see anyone paying for a slightly more polished version of this hack. A free one will very likely appear sooner or later, without our involvement.
a1ex speaking from my experience, I think there are enough users who would be willing to pay for the development. For porting ML to 5Dm4 or even R5/R6. And this would be really the best time for the switch -- there's a lot of interest around R5/R6. And it's not just the timers...
I've been professionally shooting ML raw with 5D3 for years. The 5x3 48p is dated, but there are still not many other options. Blackmagic has BRAW (not raw), cropped sensors, and plastic bodies. Sigma FP is nice but quite limited and the fullHD line-skipped mode is "meh"... Even if I would be willing to spend 10k+ on a Cinema Camera, the C300mk3 is still S35 only. And the C500mk2 is way out of budget of independent filmmakers and high-end documentarists like me.
There really are not many options that are full-frame with raw, sharp full HD and at least 48p. Not to mention that amazing UI of ML.
Recent developments with cropped 4k raw and gray preview are nice, but not so easy to use in a real-world for some serious work.
Maybe it's just me, but I really think focusing on the high-end camera will make much more sense. People who use EOS M are lowe-end hobbyists who most of them already switched to some other cheap cameras. If you will be able to port ML to 5Dmk4 (which is 1500 eur used) every film student and indie artist will use it.