Or a database or something similar? A filter? A sitewide item search page? Sorry this is silly and a bit personal, but my reason for suggesting this:
I spent a really long time working on a CA piece because I really wanted it for my wolf as a character. I had scoured the CA marketplace with no luck. Unbeknownst to me, someone had made the exact item I was looking for, but sold out of them, and therefore it didn't show up on the CA shop search. While they're not the SAME, the pieces are extremely similar and I feel bad because I don't want to make the other person to notice and feel like we're competing in sales once mine gets approved (already thinking I'm not gonna restock once it sells out because theirs was up first). I'm also a little miffed because I just spent so long making a different version of something that was already on the site. I likely would have bought the CA already available and saved up my CAT for something else. I can already see this happening again in the future for others as well, and think that a feature like this would save a lot of anxiety.