Tribblix is an operating system derived from OpenSolaris, OpenIndiana, and Illumos, with a retro style and modern components.
NEWS: September 29th 2015: Milestone 16 released, with many updates. This updated release initially available for x86. (Release Notes.)
Update: April 20th 2016: Milestone 16 available for SPARC. (Release Notes.)
It's proved that the concept can work, and while it certainly isn't fully functional, complete, or yet recommended for production use, it's getting closer. You can download the image, install to a hard drive, and use it.