Build and Design new functionality to existing Wordpress e-com site

We have an existing Wordpress/Woo Commerce site that we want to add a new purchase process/feature to. We have our site, and our store, this will be a 3rd part of our shopping experience. We sell prepacked gift bundles that we create. Our store is fully setup to sell the 15 products we have, and we have been live for about 2 months. Our homepage and store do not need to be redesigned and are fully functional. The new addition to the site needs to have the same theme/look as the homepage and store. The site has a very professional custom theme that has an elite level feel and function. We need this same level of design/function for this project. What we are adding is a "build your own" bundle feature. There will be 2 links on the homepage, one to our "classic kits" and the other to "build your own" kits. Creating/designing the "build your own" section is what you will be doing. In this section there will be 9 to 12 categories, for about 400 small products/items. Customers will be able to add any of these small items to their kit. There is no Woo Commerce add-on to bundle the way we want, this functionality will have to be custom built. Each category page will have dozens of products. Each product will have a product pic, title, and price. You will be able to add items to the kit right away, or click on the product for a product description page. On the right of the screen you will see a live view of what is in the kit, you will be able to "x" items out, and if you have achieved the minimum amount of goods (in $$) needed to place the kit in to your cart. On a portable device the live kit will be a button on the right that when pushed will bring up your kit, and it can quickly be minimized back to the button. Once the kit has the minimum cost of products the buyer can add it to their cart. When the order is processed we need a custom packing slip for our pickers that also has any gift message the customer adds to their order. This packing slip will be used for us to put the kit together, and will be shipped with the order. We do not want any pricing information on this slip, and it needs to be designed for looks including our logo. We need the site built on a staging platform before going live to make all the additions. We will need you to ensure after the site is ported and live that the functionality is flawless. You will be required to have experience porting Wordpress sites to new hosts. Please send us examples of Wordpress sites you have built/designed in the past. Please ask for any additional information, we can also send you our web address to the site you will be working on.