Here's my thought.

¤ One person permanently sign a file (being the first signer), and then just have sub-signatures of users that will contain not only their signature, but a 0-10 rating of the file.

A common list of guidelines for ranking could be made for different types of media.

(Should/Could there be a limit on sub-signatures per file? 20? 50? 100?)

Signatures should not be able to be removed, of course. Too much room for tampering. Possibly be able to remove your own signatyre, but nobody elses? (there should be a minimum limit of characters of 8, and 2 numbers/symbols in the password)

I would only suppose that signatures couldnt be remvoed from files, mainly because of malicious users. Files that are rated should be averaged to attempt to weed out malicious ratings, and create a fair assesment of the file. Also, your own trusted keys could carry more weight than the public averaged rating (essentially two ratings 1/2 (1 being trusted rating, 2 being public rating)).

Thats what I got so far. I'm prietty sure theres a better way to handle this, soo, if you have an idea, shout it out.

Edit: Whoops, meant to address your issue. Adding many security enhancements to Gnutella would be needed. Some sort of IP masquerading, and encrypted file transfers between users (as i said, SecureIM style (like in trillian). More than just those things, though

Then, pseudonyms would keep identity hidden. (I dont have much else, mebbe I should read up on how gnutella works internally, and more info on public key exchanges, and just brush up on this in general).