This was possible through hex editing:
1) Locate the trust or NPC dat file
2) Locate the dat file of the gear you want removed
3) Open the piece of gear's file with a hex editing program and read the first and last lines of code
4) Find the same lines in the trust's file and delete them plus everything in between
5) Save and replace the old file
Haven't tried it yet with adding or replacing gear but I don't see why it wouldn't work; similar methods of copy/pasting hex work to combine gear pieces (like say, glasses + hat).