Link Building for a site about Social Marketing Bots

We run a review site for bots used in social marketing (FriendBlaster Pro, Hummingbird, Tube Toolbox, etc) and need one way links coming in to the site. Links should be posted in Blogs and Forums related to Social Marketing. Post your bid, and PM with a detailed proposal of exactly what you will do. We need a minimum of 50 One Way links, all legitimate that will STICK, that are "dofollow" links, and that Google likes. This must be a White Hat effort - nothing shady, and no shady websites. Each page that you put a link on must be PR4+ and be related to Social Marketing. Only one link per website and per IP. Payment will be as follows: NO Pay up front. I always pay for work completed. Once the links are in place, I will need a list of the URLs to EACH LINK so I can check them. 30 days after I recieve the completed list I will check the links to make sure they are still there. Any that have disappeared will need to be replaced. At that point, you will be paid in full. Please bid appropriately given my payment conditions. There is also a lot of opportunity for future work, so please do your best on this!