Most extreme examples of the "Glass cannon" archetype in boxing?

YES!

I've met Eddie, really nice guy, watched him perform live for the first time back when he was still undefeated (nearly a decade ago!) on the Mike Oliver vs. Rey Lopez undercard (I sat two rows behind Joe & Teddy) and remember being guardedly optimistic that we might have produced a KO artist to rep the Commonwealth and go on to make some waves on the national scene, maybe headline some ESPN cards or something...and then a very short time later it turned out the chickens had indeed been counted before they hatched.

Total glass cannon. If we fought I'd be reasonably sure of putting him to sleep if my fists got there first, but would be worried about him getting in the first lick.