Dolphin
Samuel A. Falvo II's Dolphin is an OS for PC and compatibles; the project has been going for some time and has undergone several conceptual changes. Samuel has adopted a virtual machine scheme, where only a VM runs in ring 0 and all the rest of the system is implemented as ring 3 shared libraries (much like AmigaOS). These libraries use VM calls in order to access the underlying hardware. There is actual code floating around for this project, such as a bootsector that you can tune to boot your own protected mode OS. There seems to be actual progress this summer. Check all of that out from their homepage.This page is linked from: KC5TJA