There is https://github.com/containers/youki
It's also worth noting from the linked docs that crun was added as an option in OpenShift. runc is still the default container runtime, and which runtime to use is customizable on a per-MachineConfigPool basis[0]. Cluster admins have the ability to specify node groups that have application workloads requiring the performance of crun to use it.
> OpenShift Container Platform uses CRI-O as the container engine and runC or crun as the container runtime. ->The default container runtime is runC.<- Both container runtimes adhere to the Open Container Initiative (OCI) runtime specifications.
As for Rust-written runtimes, there is another project in the Containers GitHub namespace called youki[1] that is attempting to do just that.
[0]: https://docs.openshift.com/container-platform/4.13/post_inst...
Looks like there is youki [1] for that.
There's also 1 in Rust: https://github.com/containers/youki
> Wasm-native orchestrators will eventually build bridges that ease migration from or integration with Docker
That's a good point. And it's actually already happening (although not on the shared memory space yet as the post mentions).
Youki and curn (OCI/Docker runtimes) have already integrated Wasmer to enable running WebAssembly on their runtime.