HikaShop

My client has the following request: A special Holiday "Club" that the visitor can join.

Basically the site sells one type of product. The "club" is a no cost commitment to buy 3 or more of these items at once and recieve a 10% discount at checkout. The complication is that each item needs to allow a unique delivery date, delivery address, and message.

Any ideas on how to proceed?

You will have to create custom fields of the table "item" via the Display->Custom fields menu in order to ask the delivery date, delivery address, and message for each product.
Then, you will have to create an auto loaded coupon with a 10% value and a minimum item quantity of 3 via the menu orders->discounts.

And that will do what you want.

In order to do that, you will need the Business edition of HikaShop.