Between 150 - 300 Web Sites - Wordpress

I am looking to developed between 150 -300 Wordpress templates / webpages over the coming 6 months and am looking for a developer to help assist with this task. You will need to be able to take a brief and develop the pages, between 3 - 6 of a typical web site. The web pages will not be complicated and should be developed so we can modify them at a latter date. The web sites will need to be developed in Wordpress HTML 5 and be delivered via zipping them so we can remotely upload them onto our server. Most of the templates will be similar, with colour and design changes. This should be a very systemised job for the right cleaver developer. We are looking for a long term contractor that is happy to charge by the site with a guaranteed amount of sites over the year. Please quote a single web page given the minimum order should be 150 - 300 over the coming year.