Hey guys! 
I was looking for a custom renderer for my armor and I found this method in the Item class : 
 
public ModelBiped getArmorModel(EntityLiving entityLiving, ItemStack itemStack, int armorSlot){
   return null;
}
 
To do that you need to create a new class that extends ModelBiped : 
 
public class MyCustomArmorRender extends ModelBiped{
      public MyCustomArmorRender(){
            //load the normal player model from ModelBiped
            super();
      }
      
      //self explaining
      public void render(Entity par1Entity, float par2, float par3, float par4, float par5, float  par6, float par7){
      }
}
 
.....and thanks to the 'Advanced model loader' in Forge you can render a wavefront object for your armor. 
If you are done with your render you can bind the texture for the model with : 
 
public String getArmorTexture(ItemStack stack, Entity entity, int slot, int layer){
}
 
in the Item class. Put 'return new MyCustomArmorRender();' into the 'getArmorModel' method. 
(I hope it was not pure luck that it worked for me, correct me if I'm wrong)