I understand that there's no additional "Mercantile check level 2" dialogue to indicate you've unlocked the second-tier of special merchandise, but would indicating items generated by unlocking the second-tier with a red square instead of a yellow-orange square fit the theming and show visual progress?
I've made a simple mock-up with three items each using a different style of incorporating red into the palette for the "Special Merchandise" squares to denote second-tier items. The remaining items have not been altered.
Edit: I stand corrected, Kevin just let me know he got some new gear in after I passed 80 Mercantile. I think my suggestion still has merit, though I'm happy to see the merchants acknowledge the player's increased Merc score.
