Yes, I think we should add a reputation stat. Right now, we have customer loyalties, but they are specific to parties.
Reputation could be built by parties being successful in dungeons with stuff bought from your place, as well as marketing measures and trophies.
Would reputation be a single stat?
I can think of things like reputation for fair prices, reputation for fine weapons/armour/whatever. reputation for selling needed items (which I guess is something like loyalty)