And yeah, using a thing that modifies all shops probably isn't to be desired... um, I think I've seen some MV Plugins at least that let you do like "sell shops" where you can sell only certain things, lemme look and see if I can find a VX Ace script of the same thing.
Edit:http://himeworks.com/2013/02/sell-only-shop/ seems to be a perfect option, basically you can create a shop that you can ONLY sell items at, and decide which ones, so you could basically say "I want to only sell items" and then select all your stolen goods! :D
That's not a fence at all! It's just a lowly post.