rate & reputation plugin?

Hello,

i am wondering if someone already developed a plugin that enables a rate&reputation system that f.e. eBay uses. Basically it enables people to rate other users postings (and maybe also comments) and thus enabling users to get a certain reputation. These reputations than can be used to filter and sort postings (and maybe also comments). F.e. i only want to see the postings of users with a certain reputation or higher, or only postings by users with a certain reputation appear on the homepage.

I know about the sxore plugin but i don’t want an external solution.

cheers, Olaf