I'd really like a precious metals backed (crypto) currency. Bonus if the technology platform behind it is MONERO

Governments will never allow this.

A metals coin would fixate the mass / weight and ratios and it cannot be changed until earth corporations start hauling back asteroids from the asteroid belt, which would be an enormous economic disruption. (imagine bringing back a solid gold asteroid the size of NYC? what that would do to gold prices) When that happens, we're going to have to have a global entity act like a DeBeers and control / regulate the slow introduction of refined into the market