結構いっぱいありますね、ＯＯＯＳ
＃ふぉろー、と。

Apertos - http://www.csl.sony.co.jp/project/Apertos/index.html
　Reflective Object-Oriented OS from Sony Computer Science Lab.

Paramecium - http://www.cs.vu.nl/~leendert/paramecium.html
　Simple, flexible, adaptable, extendable OS used to explore
　tradeoffs between user processes and kernel boundaries.
　Services provided by objects named in a per process name space.
　Supports parallel programming.

Moscow - http://www.web-sites.co.uk/jules/moscow/
　Main ideas based on OO architecture of languages like C++,
　mainly involves automatically generating virtual method tables
　at load- or run-time. Applications then become, at a basic level,
　object libraries that can be reused or altered individually.
　Patch objects can replace parts of existing applications,
　for high user flexibility and configuration.

Object Oriented Operating Systems - http://www.cs.arizona.edu/people/bridges/os/oop.html
　Short, annotated, alphabetically sorted list and links,
　part of larger system.

PEACE: Process Execution And Communication Environment - http://www.first.gmd.de/peace/peace.html
　An OS family with truly object-oriented design developed
　at GMD FIRST. Emphasis: performance, configurability, portability.

SOS: SOMIW Object-Oriented Operating System - http://www-sor.inria.fr/projects/sos/
　Most interesting research results: simple, generic,
　powerful object model; the concept of Fragmented Objects
　to structure distributed abstractions; developed flexible
　naming service, dynamic linking package, library of
　application oriented communication protocols.

The Evolution of OS Design - http://freshmeat.net/articles/view/237/
　Object Operating System, OOS, pronounced ooze: attempt
　to create a new OS architecture, designed to use a filesystem
　to do many tasks usually done via various means.
　Design philosophy much inspired by Unix and Plan 9,
　but does many things uniquely, trading compatibility
　for simpler design. [Freshmeat]

Athene - http://www.rocklyte.com/athene/
　Next generation, commercial, kernel independent,
　all object and component based computing environment
　and OS that users can design to their specifications.
　Backend is built to run in almost any environment.

Unununium Operating Engine - http://uuu.sourceforge.net/
　Claimed as a radical new approach to OSs: no kernel,
　self-modifying cells (objects); single-address-space,
　useful where memory and CPU power is limited, and maybe for AI.
　Written in self-modifying, modular assembly language. [Open Source, BSD]