Ok. In my first post, I'll show you my progress with my Librarian Dreadnought. Haven't thought of a name for him yet but I'll do some fluff research and post when I come up with one.
First, I started with an old, metal Venerable Dreadnought kit. You'll see it takes up most of the conversion with the torso, legs and shield plate on the right arm. For the arms, I used the plastic arms of the Ironclad Dreadnought kit. The right arm is a basic Blood Fist with Heavy bolter with the Venerable arm shield plate added.
For the left arm, the army book states that it's a Force Weapon. I saw a good conversion on Dakka Dakka that I really liked so I copied how he did it basically. He took the left arm of an Ironclad Dread kit and filed down the chainsaw weapon. Then he cut out a blade to fit exactly over where the chains used to be.
As you can see in the picts, wherever there was a skull I added the ram horns that is typical with Librarians. I also added a Psychic Hood which was basically a space marine shoulder pad cut and filed to look like a Psychic Hood. I used green stuff to create the power cables going into the hood. Also, I took a small skull plastic bitz and added greenstuff horns right above the Psychic Hood. The Librarian Book was taken from a generic Space Marine Librarian model. I used part of a banner staff to keep the book upright with two filed ammo boxes to keep that steady.
Next steps, I'll be using more greenstuff to put ornate patterns on the Force weapon and part of the arm. Right now I'm looking for suitable power cable bits that can go into the blade and make it look "powered". More updates to come.