Good Green web hosts

Due to nature of our business we would like to shift to a green web host to give it a good authentic feel as our business revolves around wellness and natural therapy. I have been looking for some green web hosts but all of them seem like to cater to small sites with plans ranging from 3-10$/pm. We are currently on rackspace cloud ( 4gb instance ) and have been looking for a similar config but with a green host, one option is to negotiate with a green host for a dedicated server but I was wondering if there are better, stronger ones out there with a reputation to host sites with decent traffic.