Looking for web designers for a constant cooperation

We are a web development studio and we are looking for web designers to cooperate with in a payment-per-project basis. We usually need 3 psd files for each project: index page, category page, article/product page. If you think you can provide us quality custom templates, pelase send us your portfolio and a cost estimate for each custom template for these 3 psd files. Please take into account that we know that each project has individual needs BUT we would like you to tell us a standard per 3psd custom template price in order for us to pre-estimate our yearly budget for outsourcing. You should also be precise in your deadlines as we are going to be based on what you say to inform our customers. Please note that we are currently searching for web designers with portfolio. Web designers without portfolio will not be answered. We have to examine the quality of their work in their past projects.