Website Building Application

We are a new website hosting company and would like to explore the possibility of owning our own website building application which our clients can subscribe to, we will handle the subscription part of it seperately, right now we just need the website builder code. The application must meet the following requirements: a) The website builder script must be quick, no heavy code please. b) Require few server resources to run so it is not a drain on our servers. c) The clients finished website is to be published in HTML (small, quick to download files) d) Both the finished sample websites and the application it self needs to be tested in the most popular browsers for compatibility. Super simple editing capabilities similar to: [login to view URL] [login to view URL] [login to view URL] [login to view URL];jsessionid=[login to view URL];__lf=Static Design is to be similar to: [login to view URL] Application features and requirements: 1) It needs to quickly scale to the clients requirements allowing the user to add as many pages as they need. 2) We need a breadcrumb trail along the top (graphical not just text) showing the different creation steps (to be agreed) which they can jump back and forward on throughout the design process. 3) easy Upload for graphics and banners into a client folder . 4) Ability to upload a design for header, logo, buttons automatically replacing the ones pre installed (originals to be stored for later reuse). or choose from a small portfolio (to be added separately) 5) Pages need to be editable through a WYSIWYG which needs to be stylish in appearance and easy to use (change fonts / colors /etc..etc). 6) Typical tools available to client = contact us form. 7) Ability to Title each page, add description and metatags. 8) Templates need to be HTML created in offline editors such as dreamweaver. 9) We will need 5 example templates installed with sample websites built with the system. 10) Instructions for uploading new templates. 11) Navigation is to be agreed. 12) Image upload (automatic optimization) , resizing capability in editor and easy image placing. We just need the front end of the system which creates the website structure, pages and content, No need to worry about the back office admin part as we will integrate it into our system, because of this we will require full source code and possibly an hour or two of your time at a later date to advise on certain areas.