Simple Website Builder System

Hi guys, Hope you are pretty busy with nice projects :) I am here with an interesting project, I need a web service to be launched and the system is a Online Website Builder. What I am expecting is a fully-functional site builder extended from [login to view URL] (open source system) You can actually see that MicroWeber is a Drag & Drop Site Builder and they provide the Site Builder as free download where users can install it on their own servers and create websites. It is open source, you can download it free and test it from here: [login to view URL] Now, I need some additional features to be added to this system, they are as follows: 1. We need to launch this Online Site Builder system with Admin Panel so that we can allow users register on our site and they can create as many sites as they like. 2. We should be able to register users (both Free users & Paid users) and control their accounts (add / remove / upgrade / restrict) as we prefer to. 3. We should be able to accept payments from Premium Users (we need PayPal / Visa / MasterCard to be accepted) 4. Users should be able to create websites via Drag & Drop site builder ( (you can use the already available MicroWeber Site Builder for integrating it, so you don't have to develop it again as you can use the same thing, it is open source) 5. Free users should be able to create their websites under subdomain names (for example, John is a free user and he creates a site under [login to view URL] where [login to view URL] will be the domain of our own site builder system). 6. Premium users should be able to map (link) their own domains to the websites they created within our system. 8. We should be able to add / remove templates or themes compatible with MicroWeber system (I will create those templates, you don't have to worry about creating them). 7. Users should be able to choose between those templates or themes as base for their sites. I do NOT need any static / marketing web pages (those you see in MicroWeber site) to be created, I will do it as my own - I am a web designer & front-end developer :) But I need User Sign In, User Sign Up and Admin Login pages (you can give me those fully functional pages with forms - I will style them further as needed). I hope everything is clear. I am open to discuss it further as you prefer to. The system should be simple to use and perfectly integrated (should be ready to deploy).