Hi! I've seen your requirements and I'm interested in it, I have expertise in PHP(cakephp,CI,Zend) and Clientside (jQuery,AngularJS,Backbone.JS) and have highest reviews for jQuery (frontend). I can code OO Javascript and I can use the provided RestFul API using AngularJS.
The best way to built it with ajax is to use AngularJS or some other Clientside framework I'm not sure about the backend language u haven't specified that. let me know if u r interested