I'm not sure that a chat would be too useful...
one could go with one of those IRC thingy madoodles built right into ol limewire...
also, i suppose you could have a pluggin for other instant messengers... like, MSN, Trillian, or Mirranda

IRC would probably be easier and more...erm... betterer?

still... if some one is going to share a file with you, you'll prolly get it... eventually if not immediatly... and if you have a friend that
you want to DL a file from you can simply do a dirrect connect

as explained in this post
http://www.gnutellaforums.com/showth...+from+a+friend
rock on, eh