Change Detection Script / URL Monitor needed

We are looking for a talented web developer to build a "url monitor" or "change detection website" similar to changedetect, femtoo, changedetection, [login to view URL] etc. We need to build a modernized version of these service with a web 2.0 approach and excellent user experience. Note: We have posted this project twice - once here and once in a lower price band in order to attract a broad talent pool. If you feel confident in producing our solution for less than $1,500 then please bid on the same project here: http://www.freelancer.com/projects/Software-Architecture/Create-URL-Monitor.html Main features are : - user registration - 3rd party registration and sign in ( facebook connect, google connect, twitter connect) - creating new tracker (url+ update frequency) - sending email alerts - publishing rss feed - browsing updates - handling paid subscription and quota. - monitoring urls and storing updates( ~diffs) This service must be delivered as 2 independent components: - web front end - crawler optional requirements will be appreciated: - MVC - iterative approach with weekly delivery - unit testing We will consider solutions including PHP, Python, Ruby, Java, jquery, joomla plugin. You can either bid for one or both components. We would appreciate cost break down by feature and can supply a backlog which defines sprints and more detail. Happy to discuss in more detail with any suitable candidates and keen to commence work ASAP.