An esisiting registered member would have the ability to launch the wish list section.
Here they would set up any number of wish lists, could be a personal list of products, wedding registry, birthday gift list etc. they then would send a special URL and password to the people they want to have access to any one individual wish list.
Those people would then be able to login and view the products/gifts in the wish list and reserve the gift they are going to buy so others don't purchase the same gift.
To make the process easy for the wish list owner to add products I would like to use a Google toolbar custom button to launch the wish list and pre populate URL/shop title. (refer attached for more details)