I've seen a Extended Version of the Dino de Laurentis film. I think it was shown on the Sci-Fi channel one time a year ot two before the mini-series (which I didn't like as well) There is a part where Patrick Stewart, as Gurney Halleck sings a song while the group is conferencing about Arakis. Paul and the Duke share a little chuckle when he's done. It is a hoot, but Patrick Stewart does sing well!
The extended version is an atrocity. It was done without Lynch's consent, and it does have some deleted scenes restored. However, whoever did the editing reinserts some of the same scenes over and over and over again. It was such a botched job, that Lynch would not have his name appear on the credits, so the director is credited as Alan Smithee.
BTW, I don't know how many people know it, but David Lynch has a cameo in both versions. He is the man working on the spice harvester, who argues with Duke Leto about leaving all of the spice.