http://joeduffyblog.com/2015/12/19/safe-native-code/ and the rest of that blog on Microsoft Research's Midori research OS, based on C# and type safety rather than traditional process-based (i.e. Memory Mapping Unit-based) security
https://sel4.systems/ for a proven-secure (with many asterisks) native-code microkernel
MirageOS (OCaml) and similar (often Rust-based) unikernels
... and of course, the rise of the heavyweight microkernel under the name "hypervisor"
Each of these ideas has very serious downsides, but each also has earnest proponents.
Assorted pointers:
http://danluu.com/clwb-pcommit/ on the speed of modern persistent storage and the need to get the OS out of the way for best performance
http://blog.erratasec.com/2013/02/custom-stack-it-goes-to-11... on the speed of modern networking and the need to get the OS out of the way for best performance
http://joeduffyblog.com/2015/12/19/safe-native-code/ and the rest of that blog on Microsoft Research's Midori research OS, based on C# and type safety rather than traditional process-based (i.e. Memory Mapping Unit-based) security
https://sel4.systems/ for a proven-secure (with many asterisks) native-code microkernel
MirageOS (OCaml) and similar (often Rust-based) unikernels
... and of course, the rise of the heavyweight microkernel under the name "hypervisor"
Each of these ideas has very serious downsides, but each also has earnest proponents.