Comment by dmacvicar

Cosmoe and VitruvianOS are two different approaches of "Haiku" you may find interesting.

Cosmoe works at the application toolkit level, allowing to build and run BeOS/Haiku apps on Linux. The toolkit is then implemented using Linux classic APIs.

Vitruvian is Haiku on the Linux kernel (with some extra modules).

https://gitlab.com/haydentech/cosmoe https://v-os.dev/