For the surcoat, I'm using the McCall's 5500 pattern.
Since Vlad Dracula was in the Order of the Dragon, I needed a good dragon for an applique. I needed it to work well as an applique, but not look too much like the Welsh dragon.
I'll be doing it in black, with red accents, like this:
You could also take a baking sheet and cut out metal scales. Really not much harder to work with than the leather. Historically you don't see much leather used that way. It was labor intensive to make and held up for almost no time in combat. As far as constructing the actual arm pieces I would put a backing; suede, light leather or heavy cloth and then drill holes in the metal scales top end. Stich (or rivet) the scales to the backing and just over lap them. I guess craft foam would work also but I actually make functional armor vs cosplay armor.
This should get you something that looks like metal armor, even though it is still costume light.
If I was actually making such a piece I would cut several lames vs scales, basically the width of the piece and then bend them into a curve. I would rivet 3 leather straps down the length and then put buckles on them. Overlap the lames and you now have floating and very flexible metal armor. The actual shoulder would buckle or rivet to the neck piece. The neck piece is not hard just take the same pattern you used, it is perfect, divide the pattern into either half or quarter it, It would then be riveted to a backing or perhaps to straps under the metal.
You could also take a rounded tube like a milk jug (Perhaps PVC) or something and then cut pieces for the armor and paint. Still appear hardened but not metal
The pvc idea was used to make all the chain armor in Lord of the rings for example. I have thought about making some plate armor pieces in this way, just no time.
For the applique you could see if an embroidery/ screen printing shop could make it for you. You can just take in an image of a dragon that you want (so long as it's not copy-write) and tell them how large you want it to be. You could maybe even take in whatever you want the applique on and they can embroider the design right on to it. My oldest daughter works at a shop here that does that kind of stuff.