Might be a good idea to sell an electric engraver and or stamp kit in your store too... Also, if you could make some kind of rim and or a spacer on it that held it closed tight with a padlock I think you might sell more. As is the tamper tag with a padlock would only tell you if it had been compromised not keep people from peeking if they were determined.
Great minds think alike! We already have some 7200 speed engravers in and will be adding them as an add-on today. We tested several models to find one that was strong enough to engrave. We are looking at metal stamping kits as well for the future. The 4 slots on the edges are sized at 8mm to fit many standard padlocks as well.