Need some CSS help (multiple projects)

We are a team of senior PHP Web application developers in Phoenix, Arizona. We have many projects going on all the time, and are light on CSS experience. We would like to engage the services of an honest and hard-working CSS expert who can work with our designs and fix/optimize issues as they come up. We would like to engage the expert on a per assignment basis, but our real goal is to develop a longer term relationship with someone that can work as a part of our team. This is NOT a full-time position, full-time contract, etc. Its small, sporadic jobs as they come up. But we need to know there is someone we can count on who can help us out as the need arises. If you have at least 5+ yrs of CSS/HTML experience, then we'd like to hear from you. We are NOT interested in working with companies, body-shops, software houses, etc. This is for a solo freelancer only. And its small projects as they come up. As of the writing of this post, we have 2 such projects ready to go.