Online Designer for Phone and tablet cases (Opencart)

Hi, we at [login to view URL] are going to start selling customized products to our clients in a new store at www.art4tech.com. It will be a multivendor online store, were all clients can design cases and sell it, getting a commission every time the case sells. We need to implement a online designer to include in the store, allowing customers and sellers to design the case. Have [login to view URL] as reference and especialy [login to view URL] We will have several case models (iphone 4/4s, iPhone 5, iPad, with inside in silicone or without, etc...). The customization can be made of two different ways: - User starts from a blank case and adds images and text. He must be able to rotate, change font, etc... like in [login to view URL] site. - User starts from a case we already have and customizes it. So, we must be able to say if a product is customizable, or not. The designer MUST have a 3D look, like the Zazzle designer, were the image and text "bends" the sides of the cases, and we must be able to have several views (side, front, etc) of the object.... just like zazzle designer. We suggest using photoshop smart objects as product canvas, so we can create the templates, but we use any other solution you sugest, like coreldraw. Please look at Zazzle for reference. We can buy software that you can customize so you deliver final product. Please consider, if needed, to use the [login to view URL] code to speed up project. We prefer the designer in HTML so it can be used in devices without flash. Must be multilingual. This is just phase one....