Star Blades is an RPG compatible with original d&d. It evokes the vast universe of the Dune series, and I've been enjoying reading through it. While it does not attempt to clone Dune, it is better described as "inspired by" Dune, and you can see hints of other science fiction and science fantasy in it, even a little bit of Star Wars and maybe some Traveller.
I'm not sure I'd play it as is, but I think it is a good starting point if you wanted to play a Dune style campaign with OD&D rules.
Star Blades assumes you are playing a human (though an addendum adds other races) with the choice of 5 different classes: Empath, Face Dancer, Mentat, Telepath and Star Warrior.
Empath is a healer and defensive class. Roughly analogous to a cleric in traditional D&D.
Face Dancer is a thief/assassin. If you've read Dune Messiah you will recognize the inspiration from the character Scytale.
Mentat: is a human computer
Telepath: is a sort of psionicist
Star Warrior (Fighter): this is basically a catch all for a Sardauker or Fremen warrior type character
The odd character class choices don't quite fit, where is the Bene Gesserit class? and Fremen warriors should be different from Sardauker or Harkonnen troops.
Some characters have access to Powers. These are described much like spells in classic D&D, and even many of them are identical to spell descriptions.
There is an enjoyable section near the back called "In the Halls of Power" which attempts to simulate the political intrigue for imperial control like in the books. I would like to have seen the great houses described in game terms.
Unfortunately most of the images are clipped from a hodge podge of sources such as screenshots from Star Trek or the Dune movie, giving the product an inconsistent feel. I'm not sure what I'm supposed to picture in my mind's eye while playing.
One thing I like about the rules book is that it is similar to Swords & Wizardry in its brevity and conciseness.