Wouldn't work.

What's to stop anyone from putting together 100 10MB files of random bytes and sharing them? According to your post this could potentially give them unlimited access although they are essentially sharing nothing.

If you worked on the useful aspect then this would penalize people sharing the less well known files. Just because Bob is a Thomas Tallis aficionado and has all of Mr Tasllis's fine works of choral work ready for sharing, according to you idea he would get very little bandwidth because very few (if any) people would want to download form him.

In addition, the protocol is open for anyone to create a client against. For example, the number of files and total size is simply a single response returned as part of the PING message. Therefore any client can theoretically falsify the figure.

The issue of freeloading is a difficult one, but probably difficult, if not impossible to enforce because of the very nature of P2P.

Rachel