The problem is I can't overwrite the default farming and/or population buildings to accept a custom special item.
The Relay Hypertransmitters added by Industrial Evolution can be installed in vanilla Military Bases/High Commands, so unless Hartley did something outrageous there, it's doable.
Unless you mean that you'd just prefer to avoid tinkering with vanilla industries, in which case: I can respect that.
I don't want to duplicate the functionality of the historian, so I'll have to look into whether they can give the player locations of special items, or if it's just blueprints.
My historians offered me the locations of special items a good bunch of times(and not just ones you can get by raiding core worlds). Some problems with that, though:
-You first need to give them all the donations they ask for
-If your playstyle leans towards exploration(like mine), by the time you give them the donations and meet them again, there's a good chance that you'll already have the special item they'll offer directions to
-It costs a whole 4 story points, which again isn't worth it if you tend to explore everything
So yeah, provided it's sufficiently demanding, I'd say that a DEA-based special item crafting system would have its place.