Outsourcing Website Design Services

We provide solutions to the automotive industry and I am in charge of the eBusiness area of the company. I provide all types of integration between systems and have also begun providing basic website design services. This is an area which has received quite well but it is not something that I want to continue doing in house. I am looking for a 3rd party to provide my company with web design services. The pre-requisites for this project are as follows: - Design must be of excellent standard for corporate automotive needs - Pricing must be provided on a measurable level i.e. cost per day or per page - Pricing can be differentiated for design vs development process - Price levels to differentaited for static development vs dynamic content - Terms and conditions are to be established upon acceptance. Our current process involves: 1 - Creating a conceptual design 2 - Getting customer sign off. 3 - Developing website for customer 4 - Getting customer signoff 5 - Delivering website. Thanks