CMS manageable online shop with several base products with different add ons available

Looking for someone to design me a site which will essentially start with perhaps four base items, once the initial product is selected the user can then select items they want to go with their item. For example, someone may select brown wholemeal bread, they will then be offered multiple items with descriptions as to what fillings they want in said bread, and finally they would select their packaging. There would also be standard products available to buy without modification. I would like to be able to track purchases, send notifications, gather mailing lists and manage stock levels etc through the site also. In the backend I would be able to select what base items are available and what add on items can go with them, whilst also adding standard products. This site isn't about sandwiches and I will discuss the final idea should I find a suitable designer.