Back order module for Magento store

We are an aerial robotics company that specializes in building and selling consumer RC products wholesale and commercially, specifically electric power systems for aircraft and helicopter models. We also sell a wide variety of accessory products such as propellers, motor mounts, motor parts, and other similar electronic parts. We currently have a website design in the last phase of completion. This is being designed by a second party web designer with Magento as our eCommerce platform. We are looking for someone to help us build a Back Order database that integrates with QuickBooks, ECC, and our eCommerce shopping cart. Currently, when a customer places an order on the web site, our order processing personnel manually types in the sales order in QuickBooks Enterprise Manufacturing and Wholesale Edition 2013. The sales order will then be converted into an invoice for all “in stock items” and all “out of stock items” will be left on the sales order to be held as a back-order until they become available. The part we need custom scripted is the ability for our web site to tell our customers that their items are on backorder and split their order into a available items to bill and ship and backordered items to post as "backordered" pending the items back into stock . When a customer places an order, the items are either: A) Available B) Out of stock (and then are back-ordered) The goal is to give the customer the option to ship all available items and keep the remaining items on backorder. Also, In terms of shipping costs for the orders, we want our website to calculate the shipping cost for the order that is shipping AND the back-ordered items for when they will be available to ship. Additionally, we would like our customers to be able to login and view their back-ordered items along with their order history and pending purchases. This would alleviate our customer service team from providing continual order updates.