search engine keyword position tracker scraper

Hi, I you need to build us a web based software with secure login etc on our linux / ubuntu server. We can also add users to the system to access the data. The software would allow us to add keywords and websites. and track them on any search engine of google, yahoo and bing for the top 100 results. It would run at specified times - /per day / week / per month we choose. results for the latest crawl and the previous crawl would be show. will run multi thread with proxies, ideally build in php, sql, curl etc. Must have previous experience of scraping google, yahoo etc in large amounts, inc adding random time delays, removing cookies etc etc and building web based software like this please only apply if you have built complex apps before and have a lot of experience with making nice interfaces with great functions