What you are describing is a currency peg. This is what the Silk Road does with the black market items people buy on there with bitcoins. This is an acknowled

What you are describing is a currency peg. This is what the Silk Road does with the black market items people buy on there with bitcoins. This is an acknowledgement by the Silk Road of bitcoins being a great medium of exchange due to the difficulty of tracing them, but a horrible holder of value due to their volatility.