I can only think that the hoods are tradeskilled because they are simply too uber for a level 30 twink to wear (and based on the 2 items used to make I don't see level reqs so I'm assuming tradeskills are the limiting factor in game balance).
Only thing I can think of is a notumcomm mesh has lots of sensors in it. I wonder if someone who has one can take the mesh + a normal hood and try to combine it just to see.