I've tried to look for this myself, with no luck. It does appear that crafting keywords for categories are hardcoded.I also looked at the source code for CraftingMenu.swf but all I could find was a reference to a categories list from which the menu is built, which I assume comes out of the DOBJ.You can see the DOBJ in the Gameplay menu of the CK ("Default Objects"), where you can alter the value of keyword entries, but you can't add any new ones. There are also 2 FormLists linked to the DOBJ: MaterialsArmor and MaterialsWeapons, but adding any new category keywords to these lists did not add the categories to the game for me, so there must still be a hardcoded function in between or I am still missing something. The keyword for Falmer armor is not in the MaterialsArmor list, so that's probably why the above poster could not see Falmer Armor show up as a category. I haven't tested yet if Falmer would be recognized by adding it to the list. I did however manage to simulate a sort of menu management using different furnitures. I created new furnitures and added a custom keyword to those, then linked recipes to those furniture keywords instead. This took the recipe out of the original furniture and made it craftable in the new furniture menu. For example, at first I had made soulgems craftable at the forge. I then created a new furniture called Gem Cutter, took the soulgem recipes, and changed their related furniture keyword to the Gem Cutter instead. This made them not show up in the Forge menu anymore, but they did show up in the Gem Cutter menu and were perfectly craftable. The items still show in their original keyworded categories (i.e Misc, Iron, etc) but you do achieve some form of list management that works if you're willing to create different furnitures. For myself, to save space and keep immersion, I scaled these furnitures to a small size and put them on a shelf or on top of the original furniture, for instance my Gem Grinder is now a small dwemer looking contraption placed on the tabletop of an enchanting furniture. What you have to do to make this work is create a copy of an existing furniture (I took the Blacksmith Anvil). The important part is that the original furniture's keywords are preserved EXCEPT for the keyword that starts with Crafting. E.g. for the anvil, the keywords are: FurnitureSpecial, FurnitureForce3rdPerson, CraftingSmithingForge, WICraftingSmithing, isBlackSmithAnvil. The WICraftingSmithing keyword seems to determine which menu needs to be shown, while the CraftingSmithingForge keyword determines the list that will populate the menu based on linked recipes. Remove CraftingSmithingForge from the furniture and replace it with you own keyword, then link all recipes you want to craft on this furniture to your new keyword. I also found that if you remove IsBlackSmithAnvil (or IsBlackSmithForge) this will break the crafting menu (it crashed the game for me when I used the linked furniture) - so whatever kind of crafting furniture you make, the game must think that it the original furniture linked to the menu you're showing for this to work. Hope this helps.
