Wasn't there a key toggle that showed locations of shopkeepers?
 

….maybe I'm thinking of another game other than Drakensang, but I don't think so.

I thought that you could hit a key and make little red 'x's appear on the map and when you mouse over it, it would tell you the name of the shopkeeper and (I think) what they sold. If I'm right, does anybody know what key this is? Thanks!

As far as I remember it was depending on some of your or your companions feats (something like "knowledge of city life"? - I play the german version) , not a toggle.

yes, Drakensang did it as it should be imho. What you see in the minimap depends on character skills (NPCs for street lore, plants for plant lore, etc)

Yes, street lore, in this case.