E-Gold™ is back.[0] Now with added cryptocurrency.
Having a blockchain registry to track ownership of precious metals is not a bad idea. But as the ultimate capitalists over at ZeroHedge [1] point out it's a centralized system and vulnerable to both fraud and attacks from governments ( vaults full of gold are hard to hide and harder to move ).
0. http://www.wired.com/2009/06/e-gold/
1. http://www.zerohedge.com/news/2013-11-29/e-gold-founder-laun...