Hi,
the idea above sound interesting (it sounds like Mojo Nation [1]), but I guess Mojos can be faked. I have another idea to stop freeloading and improve download speed at once. My favourite is: Swarming.

Swarming means to distribute small parts of files all over the network and every servant takes part (even modem users). Please read more about advantages and technical details in the link above.

Also I think a philosophy of "healthy servant behaviour" is a very good idea (read more at Limewire [2]). For example a servant does allways share the download folder or _allways_ does allow 1-n upload slots (n depends on uplink bandwith) with a minimum bandwith, e.g. like Xolox does.
A Gnutella servant that does allow zero upload slots (most servants do this), does support freeloader and therefor is unhealthy to the network. Especially this behaviour must be stopped IMHO!

And finally the anonymous Gnutella network should be turned into a real community. Inside an anonymous network people intend to "take and go"... a community would encourage people to a much more cooperative behaviour. To achieve this goal there are various ideas: The users need a personal contact, a chat between clients. We should build structures which strengthen communities, e.g. more specialized horizons where people of a special interest (music taste, gamers, coders, etc) can find each other. People with similar interest intend to be more cooperative to each other. Or how about showing a "gnutella karma" which shows how much you have downloaded and how much you have given back. All this together could encourage users to be more cooperative, to be a part of the network. Let me say this again: Gnutella means sharing.

Some of my ideas. hope you like it, Moak.

[1] Mojo Nation http://www.mojonation.net/
[2] LimeWire article about Network Healt http://www.limewire.com/index.jsp/med_require