Link Building Campaign

I am looking for a long term link building partner for the websites I manage. They are across various industries and the sites have already been "on page" optimised by myself. I will need to see examples of link building experience, and how you manage your campaigns. Links will need to be from relevant websites and good resources, a mix of directories, blogs, articles, links etc... Upon accepting a bid I will be needing the work to start ASAP, with a trial campaign of around 20 hours then upon successful completion it will lead to regular campaigns.