A Smorgasbord of Operating Systems Projects
Here are a few projects I've used in OS courses in the past.
A 32-bit protected-mode operating system for the PC
Related material
A 16-bit BIOS-based operating system for the PC
This project was used in a second-term undergrad OS class.
Students build a small OS with text windows and file operations
A small object database system
A gaggle of shorter projects
Homework related programs