The system would be a checklist, trade list, wishlist, and for sale list available for each user on your forum.
Before we go further, think Custom Profile Fields on steroids.
This will allow your members to...
Manage a collection (toys, trading/sports cards, stamps, movies), and have a URL to point others to show it off.
Manage a trade list - List all items of a select area available for trade, specific to your topic, controlled by you. Personal URL for each member.
Manage a for-sale list. Similar to the trade, except it is specifically marked as for sale.
Manage a wishlist - Mark off all items you want, and send the URL to a friend, parent, girlfriend for your birthday, holidays.
Searchable - Search for members with XYZ checked off.
Visable to public - Each list can be pulled and displayed on its own page, for each user.
Controlled by Admins/Staff - Items are created by you in the admincp almost exactly like creating Custom Profile Fields.
URL based links available for insertion in postbit or member profile (example: click here for my wishlist, click here for my trade list, etc)
Print function: Enter all the items you have, go to page, hit print, print out all the items you have for home management.
Checklist Category 1:
Item 1 -> (Checkboxes->) Have it, Have it this way, Have it that way, Dont have it, Add to wishlist, Add to trade list, Add to sale list.
Item 2 -> (Checkboxes->) Have it, Have it this way, Have it that way, Dont have it, Add to wishlist, Add to trade list, Add to sale list.
Item 3 -> (Checkboxes->) Have it, Have it this way, Have it that way, Dont have it, Add to wishlist, Add to trade list, Add to sale list.
Item 100000 -> (Checkboxes->)Have it, Have it this way, Have it that way, Dont have it, Add to wishlist, Add to trade list, Add to sale list.
If you checked off "Add to trade list" for item one, another member could go to a page that lists all your trade items, example:
If you checked off "Add to sale list", another member could go to a page that lists all your sale items, example:
What makes this different than Custom Profile Fields?
This is in a seperate set of tables in the database.
Easily turned on and off without disabling or modding regular Profile Fields.
The results are show on their own pages, not on the member profile page.
Designed to manage large checklists, with potential for thousands of item entries.
Checklist "starter page" showing recently modified checklists, sale lists, trade lists.
Categories for items - Custom Profile Fields do not have this option by default.
Why use this?
Many of the store systems are large and tedious to manage. They often have functions not needed by most sites.
The auction style systems are not for everyone, most users still prefer classic Buy Sell Trade methods (post a thread, Use PM to trade).
Compliments rather than replaces Buy Sell Trade forums.
It allows collector based sites to offer a checklist system which is controlled by you, so it is linear and interactive.
Offers a service to your members, allows them to manage their hobby (or whatever else) through your site, guaranteeing their consistent return.
I know there are hacks available that if merged, can somewhat mimic this using existing custom profile fields system in VB. However, I think a seperate and dedicated plugin would be better, easier to expand without mucking up core VB stuff.
Ability to enter an Image and external (or internal) url for each entry (admin controlled). So you enter a Name, URL, OrderID, and Checkbox Selections for each entry. Mabey have a custom field system applied to the creation of each category, plus the input method system. That would be ideal for wishlists especially.