I'm not sure if I mentioned Emperor of the Fading Suns before as having rather obvious Dune influences and themes, but apparently there was another game (which was sadly cancelled) that also went in a somewhat similar direction. The game was called Mech Wars and then Metal Lords, and only a handful of pre-release screenshots and a non-playable demo appear to have been preserved. Here's a video of the demo:
https://www.youtube.com/watch?v=W5HpANBASHY
The premise seems to have a feudal interstellar empire with noble Houses, but unlike Dune, war is waged with giant mecha robots. Recently I found several preview screenshots on the SCORE magazine coverdisk (issue No. 21, found here), and uploaded them:
https://imgur.com/a/2IzGgMV
The shots show characters from noble Houses named Paul Strader and Vladimir Sardonis, which I believe are pretty obvious references to Paul Atreides and Vladimir Harkonnen:
Note how the two characters on the latter two screenshots (which are BTW not the characters mentioned by name in the respective images) also look very fitting for Dune character art.
Another noble House is called Ordeus.
The game was developed by SimTex, the team behind Master of Orion and Master of Magic.