Closest thing I've found is the Forge HUD (Hud_ItemForge.swf) but I'm guessing that can't be manipulated in a way that would aid my cause.

You probably most likely consider looking in City properties and Unit Properties. Or anything tied to structures you build in cities.

It might be quite dicey to found since it can be hardcoded and looking in unusual places like Interface, Title or Equipment rpk can be considered.

However most things revolving around forge is anyway tied to abilities ranging from costs or settings like allowing particular abilities to be available on all items or none at all.

I you completely want to redesign item forge to something else I'm guessing your out of luck. It's possible to remove, add or balance cost on abilities and also move around abilities only available on jewelry to also apply on mount etc.

Or simply remove the item forge from ever being built.

At this point I'm almost convinced its a figment of my imagination, or like you said, hardcoded into the engine files.

Yesterday I spent hours looking through every RPK in the game and DLC. I thought it would be scripted but cannot find anything related to it. I guess I will try another pass before I give up.

Appreciate the input.