I suggest this thing:
- No need to show User's Inventory for who dont have anything in their inventory. This will help alot for not slow down the site because a lot of query use.
- Can order the categorie via ACP. Some Categorie need be first or some need place below.
- Equip Item: Let users choose their favorite X items and display only those in their postbit. Like the Upper post I say. Because a lot of image will slow down the page.
- I think we just let 4 slot to equip the item in their Postbit. More will slow down.
- More Information about Items: when I click on the Item Icon or their name, this will show me other page with their full information. This will help alot.
- Items in Profile - Shows all items. This will be cool.
- The admin can remove the item of member via Usercontrol.
- The Statistics for this shop will be usefull to see how member buy/sell the item.
- The Option to change the rate of "sell"
- The option to hide the item for guest!
Will add more suggestion.

This mod will be cool. Where is the author? :|