Opencart extra features to be built in

We have an opencart shopping website which we want to add the following features to, i will share my website URL with you once i am confident you are able to do the work: The features we want adding to our website are based on a website that’s already online called threadless. 1. The first feature we want adding is the ability for our users to create and design his/her own t-shirt designs and submit them for selling on our website. The user submission of the designs is done through a download of a PSD file (which we will provide them) and then they upload of that PSD file with their design added through the submission page here [login to view URL] when they are logged in (you might need to log into to see the submission page on the threadless website). The submission page is going to be designed slightly differently to threadless page. Please see the word document attached to see the layout and text of this page and how it should be. Here is the submission kits on threadless - [login to view URL], we are getting our submission kits done for our website but for now we could just use of one of theres to get it working on our site. 2. All the users designs should be collated into a profile page/shop type page similar to the threadless page here - [login to view URL]@[login to view URL] 3. We want a chat/comment capability on our product pages so once the user is logged in he is able to discuss people’s submitted designs with other users of the website. We want to add this feature on our product pages. The chat/comment feature on threadless is here - [login to view URL],guys/style,shirt 4. The last thing we want adding is a tabbed browsing feature of a products pictures on our product pages like on the product pages of the threadless website here - [login to view URL],guys/style,shirt (see the browsing tabs above the picture - mens, womens, childrens - we this adding to our product pages). Please create everything using VQMOD feature on opencart so all the features process on the fly this will ensure that all the extra features we are building will not interfere with any of the core or main files and code of opencart, also we have a t-shirt designer plugin software embedded into our opencart website and we don’t want these extra features to effect or change any of the files associated with this plugin either. This is very important. In the long run we are going to need updates on this so i would need whoever i choose to be available in the future for this work.