I thought HUGE is simple and flexible?

It does explain a lot of basics and also details how to include hashs into binary Gnutella messages (did you recognize that you have to encode 0x00, also compatibility with other/older clients is guaranteed)? If you think it can be done easier, write a paper... I prefer easy solutions. :-)

PS: What you said about swarming and a list of alternatives downloads. Yes, this is another advantage when we have hashs and Queryhit-caches. I'm a big fan of superpeers, hashs, swarming and multisegmented downloading. :-)