A site that shows the traffic on other selected sites

Hi all, I want a site similar to that of alexa which shows web information about a website.I want to know the web traffic of 50 websites(i might wanna increase this no: later) of my choice.I want the traffic updates on these sites fortnightly. I am not looking for a crawler which grabs data directly from Alexa or any other sites for that matter.I need the data i.e traffic and other related data on a database from which i can grab all the required information and put it wherever i want. Please mention the technology in which you are planning to work on and a bit on how you are going to do [login to view URL] are free to suggest other addtional features that you could provide along with it like the demographics related to the site. You can provide your suggestions on the matter. Regards, Lares