I saw a really cool lighthiker piece of homeade gear I plan to reproduce myself.
It was a military rain poncho with some cut down fibrglass tent poles that made a tiny one person tent(no floor) and weighed next to nothing.

I think the whole light gear thing is not about leaving gear behind. You could just take a knife and a lighter and make a fire but that is not nearly as cool as having the latest lightest MSR stove.

My minimalist emergency kit is a bic lighter or firesteel,mora and some water purification tablets. I sealed one in a foodsaver bag and duct taped it to my life jacket. They are cheap enough to stash everywhere.