I've made all sorts of modifications to weapons via Wings3D. You'll also have to go on the taleworlds forum and get the program that allows you to add the meshes, textures, and 3D models together.
It's pretty easy to mess around with. You can do all sorts of fun stuff to the items. I added a horse bone skull as a helmet, the barbutte plumed of course, and I fiddled with the norman helm with faceplate to add heraldry to the faceplate itself. Very cool program.
Edit:
That program is called BRF Editor