Wordpress Mu Hacked

I'm trying to get get a modified wordpress mu service online. It would be hacking wordpress mu and using plugins to create a system that would allow for people to sign up for a blog, then invite users they want to contribute to that blog. They would also be able to set up their blog as private or public. I am set on using wordpress mu as the core of the system since it basically does everything I'm wanting. I just need someone very familiar with wordpress core, that is comfortable hacking core code and finding plugins to do what I need. I can give more information to those of you that need it. But please don't bid if you're not very familiar with Wordpress.org. I need someone very comfortable with it. The designs of all of the pages are already completed, but I will need someone to build out those pages as well. I'd want it to be very clean css and there would be a few little ajax tools throughout the site as well. Thanks.