I need help finding an e-commerce store that supports this idea

I found my way here from http://ift.tt/1zzcDGl. I would like to design a 1 page wordpress e-commerce site. Here is a link to what I have in mind for design.

The user would select both a variation of item #1 and a variation of item #2 via radio buttons. There may be more than 4 variations with a slider bar as drawn or...??? Once the user selects one variation of both item #1 and one variation of item #2, the link to pay would become available. The price is static and shipping is free. Below the 'items,' there would be subsequent fields for shipping info and credit card info or a paypal link.

I hope this doesn't seem too ridiculous. The design seems pretty simple to me. I admit, I am not experienced - though I have built numerous WP sites.