Modifications to SMF Shop Mod

I'm looking for someone preferable familiar with the SMF forums and the SMF Shop mod. I want to use the shop mod to allow users to achieve reward "levels", by purchasing items in the Shop using their credits. First modification I'd like- I want to add a field to items that adds having a different item in their inventory as a prerequisite for buying the item. E.g. to buy Item B, user must already have Item A in their inventory. I'd like to be able to select the item that is a prerequisite purchase from a drop down list when adding the new item (or editing). Second modification I'd like- A way for Members to select an item from their inventory to show in their profile section next to their posts in the forum, e.g. underneath their avatar. In their inventory, in the Paid/Use column, a checkbox should be added for a user to select "Display Reward". The image for that item would then be shown under their avatar. Each user can have a maximum of three items showing at any time (three checkboxes checked).