But the one time I looked at a rust git repo I couldn't even find where the code to do a thing was.
IMO that tells more about how the project was organized and names things than the language used.
So I think probably, the best way IS to go the way linus did. Just go ahead and write a very basic working kernel in rust. If the project is popular it will gain momentum.
As the other commenter pointed out, there's Redox. The issue is that this completly disregards an incremental approach: you have to rewrite everything before it comes usable, you can't do it piece by piece. Currently the approach of Rust for Linux is not even to rewrite things, but to allow writing new drivers in Rust.
Trying to slowly adapt parts of the kernel to rust and then complain when long term C developers don't want to learn a new language in order to help isn't going to make many friends on that team.
Have you seen the conference video? That's not just refusal to learn a new language, it's open hostility. And it's not the only instance, for example Asahi Lina also reported unreasonable behaviour by some maintainers just because she wrote Rust code, even when Rust was not involved.
Zig is safer than C, but not on a level that is comparable to Rust, so it lacks its biggest selling point. Unfortunately just being a more modern language is not enough to sell it.
C++ was not added to Linux because Linus Torvalds thought it was an horrible language, not because it was not possible to integrate in the kernel.