Firstly 'd like to point out that the original ideas for putting Night goblin heads on Dwarf bodies, wasn't mine, here, I got the idea from CMON, when I saw this:
Obviously back then the AoW plastics did not exist, but I think Kubasa did an excellent job on those gnomes. I had that image in my mind for years and when I saw the AoW plastics I decided it was finally time to give it a shot.
I don't have any WIP shots unfortunately, but I will try and describe the process as best as I can.
Avatars of War plastic dwarf Berserker, legs, arms and torso. - here is a blog page that reviews the kit: LINK
OOP GW Dwarf warrior head (with beard of choice).
OOP GW Night goblin head (with hood).
Weapons of choice (in my case I cut the ends off of the musicians horn in the Warhammer FB Dwarf Thunderers / warriors unit (can't remember which)).
**I highly reconmend superglue rather than plastic glue as the parts can stil be separated if anything goes wrong.**
**NOTE- anywhere I mention GS I mean greenstuff, and you should always let the GS set before moving onto the next stage in case you put your finger in it.**
Trim off the bottom of the night goblins face, and a tiny bit of the bottom / back of the underside of his nose (a little notch for the beard to go into).
Trim the beard off the dwarf's head and shave off some of the back of the now seperate beard at the top. Dry fit to Night goblin head, shave more off if needed until it looks right / fits snugly, then glue into place and GS any gaps.
Take your chosen legs from the AoW beserker kit (I prefer the ones with trousers) and cut a small wedge of sprue at the angle you want the body at ( I did this to make the model more upright (helps with the head being so big).
Glue the sprue to the middle of the legs (I recommend dry fitting to ensure correct angle as it's a pain to trim the sprue piece after gluing).
Glue to torso in place.
Using a blob of greenstuff fill the gap in the torso and sclupt at the back to blend into the legs and torso.
Dry fit the night goblin head (with attached beard) and trim down the neck line and sides of the back of the goblins hood to fit. Then glue the head in place.
Use another blob of GS to extend the back of the Night goblin's hood over the torsos' back blending into the hood.
Create / cut / choose your weapon heads, glue them to the AoW arm weapon shafts and then glue the arms to the torso.
Tidy up with some greenstuff on the shoulders if required (I did on mine (not pictured above).
All in all fairly simple conversions, but getting hold of the OOP parts might not be so easy.
You should end up with something like this (additional cloaks were converted out of a GW Chaos warrior back half (dremelled to death) and an off cut from the OOP "Hairy head sprue" (originaly from the Mordheim boxed set).
Cheers for reading.