company review /scorecard site

We are looking for someone to take on a development project. We have the ideas behind the site, and how it is to work. We are looking for someone to offer design and programing expertise. Briefly the site will be a form of review postings site. We think the site can be done using Joomla, but are not sure. The site must look professional, we expect to see some sample work for anyone who wishes to bid. Also, only bid if you are capable of delivering the total project. We have had unfinished projects in the past, and don't want to waste time and money. We will only pay once there is solid proof that the project is complete and fully working. We are also willing to pay extra for a job well done, and willing to offer future work on the project. We can provide further project details via PM, to bidders we consider working with. Thank you,