You can build your own custom Linux distribution, run it in your browser, and share it with others using http://susestudio.com/ http://susestudio.com/ — it migh

You can build your own custom Linux distribution, run it in your browser, and share it with others using http://susestudio.com/ http://susestudio.com/ — it might not be what you're thinking of (as it's only a few years old, not 10 years), but it does what you mention (and more).