What bittorrent tracker can I use for a private website?

I'm toying with the idea of creating a private torrent tracker website; the ones that require registration and track their users' ratio, have "credits", and so on.

Can you list some torrent trackers suitable for this? I tried googling a bit, and I found for example opentracker, but as far as I know it doesn't provide a way to give the website the information required to track ratios, etc. Also I don't see a way for the website to tell the tracker which torrents are allowed (since torrents would be created through the website).

Thanks!