I decided to make some necks myself. I used the dimensions of the raph GH mod neck.png for width (300 px) and am still experimenting with height to see what looks best. Here's a very simple example of what I threw together in Photoshop in literally 5 minutes:

I have some pretty sick tribal/dragon design brushes so I'm planning on making some necks similar to the one in the picture. I could also use some wood/whatever texture if I find some good samples. Backgrounds could be transparent gradients, textures, etc.
I suppose I'll update here when I have some necks ready. I'll start tomorrow evening, when I get back from work.
[Edit] I just realised this post belongs to the forum section below the one I posted in. Sorry. More coffee, less posting! [/Edit]