SuperKernel

Note: the project is basically dead, as I started rewriting it but I don't have much free time to work on it.

It's basically a micro-kernel, but on top of that, instead of having multiple servers running as standalone processes, it has a modular kernel, so that each server is a module of this kernel.
The micro-kernel contains only the scheduler, memory management and drivers for high-speed devices (like gigabit ethernet NICs or video cards).