Problem with that concept is it would make each search much much slower & would slow the overall network down. Searches only find a % of the entire network. Also if you're sharing similar material & uploading it, it helps with searches in my experience.
It sounds a little similar to this http://www.gnutellaforums.com/showpo...&postcount=126

http://www.gnutellaforums.com/showpo...&postcount=246