Just wanted to make sure you knew about <a href="http://rfc-gnutella.sourceforge.net">this</a>. The one idea that you mention made me think of the QRP (Query Routing Protocol) document there. There's more info <a href="http://rfc-gnutella.sourceforge.net/Proposals/Ultrapeer/Ultrapeers.htm">here</a> too.

The link to the details of your project wasn't working for me... sorry if you already know about this stuff.

I always thought a big query indexing system like you described, would be great for putting up a website with information on the "most searched for artists" and other such categories. Almost like a Dick Clarks Top 40 list... on speed.