I think if you wanted to make some kind of "personal shop" it would be much more effective to simply integrate it into the current CS. Just add a field for the player's name that can be used to filter by as has been suggested numerous times before. And maybe also add a button when you examine a player that says "go to my store" that you can click to automatically bring up the CS search for that player's name. This way, players can list whatever they're selling and it's easy to get to both via CS and the player himself.