Web 2.0/Ajax application/site (PHP or Ruby)

I need someone talented to write a Web 2.0 application. The application needs to be written in PHP or Ruby and use standard Ajax library (like scriptaculous). Here is an overall description of the Web 2.0 application to develop: The application to develop consist of mainly 4 main features : 1- a web site where user can register and create a profile. Each user will have a simple data structure associate to him. The data structure will be filled by a bookmarklet (see below point 2). Standard features are expected : password recovery, ability to change profile information, data structure simple management (edit/delete/modify), keep user logged in, logout. The data structure will be used to generate an RSS 2.0 feed. The profile page should provide a ‘link’ corresponding to the unique bookmarklet for the user -with ability to reset/regenerate a new unique bookmarklet. 2- a bookmarklet : some simple javascript that is unique for each user. The bookmarklet will usually be dragged in the user favorite browser toolbar so it can be accessible at any time while surfing the web. The bookmarklet will let user submit information to the data structure created when they register. The bookmarklet will do some DOM manipulation and display a dialog window with some info extracted on the visited page. ? See [login to view URL] for getting an idea... 3- some private REST API that will authorize the following features : an API used by a third party application that will ‘ping’ the system to see if some new data submitted by users are available (will return the new data submitted + some user info), an API used by the same third party application to update some information in the user’s data structure (updating a few fields). Information send back and forth to the 3rd party application will be using XML (UTF8). 4- a unique URL per user that will automatically generate an RSS 2.0 feed based on the current user data structure. While generating on the fly the feed, some logic should be in place to monitor how often a URL for an RSS feed is requested. If the URL is requested too often, the system should automatically reject the incoming request (avoid abuse of the system). The URL for the RSS feed will be communicated only to the user in the user profile page. Look & feel of the overall application is IMPORTANT (including the bookmarklet). This is a Web 2.0 application and the user experience need to be smooth. Clean CSS required and good AJAX usage are required : goal is to avoid page refresh. Application need to be compatible with PC & Mac browsers : application need to work with IE 6+, FireFox 1.5+, Safari 1.3+... This is not a social networking application, there is no requirement for sharing data between users. Application need to be fast and intuitive. In addition to the logic described above, a few extra standard HTML pages will be required (about us, policy, welcome page)... Logo/images are not part of the project but if you think you have the talent for providing some nice looking design then it could be added to the project. The application will be running on a Linux/Apache/MySQL system that can host PHP or Ruby On Rails applications.