Developer needed to build online project manager

I need a basic online project management system built that over time will evolve and grow. The system is currently having the front end designed, and I am looking for someone to come and sit in our office in London and build the back end. It will effectively be a website hidden behind secure access page (login & Password). The concept behind the Online Project manager is that our clients will be able to securely log on and view the progress of any project that we are working on for them. It will initially have four main sections to the system. Schedule – Timeplans dynamically presented as a chart or table originating from an excel spreadsheet Budget – Tables dynamically generated from an excel spreadsheet. Project Assets – Asset storage section allowing all the project files to be uploaded and downloaded (via FTP?) as and when needed. Thumbnail view of the asset. Client review – FTP viewing area for Video, MP3, JPG & PDF files. (Windows media player, quicktime streaming/progressive download). Ability to write/post comments on files. The administrators will run the system and allocate logins and passwords as well as allow full or restricted access to sections. i.e. we might want to give someone access to the Project Assets section, but not the Budget. We have several users to the system: Admin, Clients, Freelancers & Vendors. If you are interested, can you provide me your contact details and daily rate, as well as a couple of web addresses of some of you work. I will then get in contact. Please can you also give me a rough estimate of how long this sort of project would take based on the information above and how you will build it. i.e. ASP, XML. A full specification will be provided before you start so that you can give a realistic timescale. Cheers Alex