Bazaar can be utilized to hold two identical unique items
That's an abuse, not a feature. You shouldnt even be getting two of the same unique item on a single event, so what reason is there that you can't just put it on a retainer?

Whatever then. Make it a special bag or something that lets you carry more unique items (Defeats the purpose of the unique tag, but whatever- since everyone hates limiting mechanics) and seperate the bazaar functionality from it. I don't want to see the unique items you're holding but dont want to sell. I want to see the stuff you want to sell.

It's called "Bazaar" not "Magical bag of holding". If it's necessary, give everyone one of these magical bags of holding and then make it so checking peoples bazaars only shows things that are actually being sold.