Site similar to hotscripts for selling scripts

I am looking to build a website similar to [login to view URL] where third party can sell their scripts and plugins. It should contain scripts, plugins for like Joomla, Elgg or other website building sites. There will be a database where Users can log in and post their scripts. Public can log in and download the scripts from their websites. So right now there should not be any option to upload or download from our site...everything will be done through third part websites. There should be featured listings which will be highlighted and be visible to all users for a price, and the rest will be free to post. Rating system will be there and users comment. There should be a blog and forum where users can communicate and the date stamp will be posted when they talked last. The categories of postings will be similar to hotscripts. Provision to upload at least 3-4 pics or screen shot of their scripts. All in php programming where it can be added later with more functions. Very tight budget has to be very competative to get this project.