The problem you run into is finding a trusted, centralized authority who would back the coin by gold - fail because you lose decentralization. Having individuals back it leaves you with no guarantee they will perform. At least with the current system, bitcoin has its own value based upon its unique features, qualities and benefits. These features, qualities and benefits are valued enough by people like me who will sell you their gold for your bitcoin.

Trader Steve
http://www.GoldStarBullion.com