[q-big]

> I remember one called SkyOS as well - it was really far along, probably killed by the lack of driver support. Unfortunately it's site seems to no longer exist.

Here is the LinkedIn page of the main developer (Robert Szeleney) of SkyOS: https://www.linkedin.com/in/robert-szeleney-26902738/

In 2009, he founded Djinnworks: https://djinnworks.at/

You can find Robert Szeleney's email address on https://djinnworks.at/team

Considering the fact that according to the German wikipedia page (https://de.wikipedia.org/w/index.php?title=SkyOS&oldid=21527...), the last version of SkyOS is from 2008, I don't believe that SkyOS was killed because of a lack of driver support, but rather because the main developer simply had to make money. But feel free to ask him directly, you now know how you can.