social network website

Project Description:
We are a startup working on a website combining social network and e-commerce. The basic coding is done, which is implemented using Ruby on Rails. We want to improve the user interface significantly. We are looking for someone who is an RoR and Ajax expert, and has 2+ years of experience in graphic design/user interface. Ideally, the person should be physically located in the Silicon Valley, and communicate with founders on daily basis. The person should be able to review our existing code base and roll up his or her sleeves to implement improvements right away. Based on the feedback of our current users, this person should be capable of implementing a user interface much better and more fun than our current UI; we're looking for "the coolness factor".