I will address the numerous good points made here because they are worthy of being addressed; however, first I have a proposition.

BitCoin has proved that an P2P currency-like thing can exist and work; however, chronic instability is an ongoing problem.

I'm not a programmer, but consider a P2P cryptocurrency with an initial centralized online exchange that the P2P program runs. The program gives more Coins to miners when the price of the cryptocurrency is deemed too high and gives fewer coins to miners when the price is too low similarly to how a government might do so. Thus, the program is able to peg the currency value and maintain long term and short term price stability.