Database website development. Longterm relation!

We are searching for a company with significant experience of building websites with custom made features. We are not interested in bidders with little feedback and/or no significant prove of skills through running websites. So please only bid if you qualify to our criteria. Communication is very important and that there is a group of people dedicated to this project and not constantly changing people taking over. Generally we are looking to built a website similar to this: [login to view URL] But we would need customized features and a comprehensive administration tool behind which would allow multiple people to work on the site with different access to features. After the basic website has been finished and goes life we are looking forward on a continuing partnership with further developments and features to add. So the first part of the project would be basically to built a page roughly reflecting the features of the sample page above. We are looking forward on receiving your bids.