ive got an idea for making the visor for the helmet seeing as, as it was put earlier, it would be near impossible to find a visor that large without modifying a fish bowl.
basically i figure you could most likely get a gold tinted visor, kind of like the ones used by bluerealm as the actual visor and then sculpt the rest of the helmet with all the details the in game visor has and whatever you have left over that your actual visor wont cover, use a gold mirror finish paint for the rest of the visor.
or you could try using multiple visors and try and glue them together somehow....just a thought
i know there is a clear plastic sheeting that you can purchase im not sure how much it is but i know you can get it. if you can get it then you can possibly get a gold tinting for the plastic after its been vacuuformed iover a lense mold. id say thats your best bet for a high quality lense if you want a solid piece instead of having to worry about glue n stuff.
just and idea
ill see if i can post a link for the clear plastic sheeting later when i have a chance to sit down.