I'm still trying to figure out how the 787 can save 15-20% (I forget what
Boeing claims) when everyone jumps for joy when something will save 1%. Any
ideas or literature out there?

Widespread use of composites might save 8-10% in structural weight
(that's just a WAG though), which means you need less lift, which means
a little less drag. Also, the engines are of higher bypass ratio than
anything else used so far. Combine that with more aerodynamic
improvements and use of all-electric systems, I can see where you might
get up to 15-20% fuel savings.