1. Backing Bitcoin would require a central authority and being decentralized is one of the key characterisitcs of Bitcoin. Without decentralization Bitcoin would loose value, not gain it.
2. If you still think its a good idea, you can go and start goldcoins, silvercoins, ricecoins or dollarcoins. Let the market decide which one it prefers. But I would take a good look at what happened to Liberty Dollars.
Gold has unique physical properties. It "backs" itself.
Backing btc requires a central organization to implement, which defeats the purpose of btc.
Bitcoins also have some physical unique properties. It "backs" itself, as its price its showing.