315584 Magento Customizations

I have a modification I need made to an installation of Magento. I am working on a wholesale costume store, and the wholesale customer needs to be able to select the quantity of each different size and color of each product, and then all of that information needs to be sent to the cart. I have attached a screen shot of how their current website gives this ability. I'm not sure what the smartest way to do this is, but I am willing to explore other ideas as well if someone has suggestions.