Following what Babylon said in here
, here is another idea directly related to the money supply. Other people would want to create other systems like BitCoin. Well, how about BitCoin having a feature called "minting service contracts"?
A minting service contract would be an XML which describes how a minting service can integrate with the BitCoin network. Basically, rather than having lots of software applications (which would have to be trusted) which do the same thing as BitCoin but with slightly different protocols and numbers, use just one (BitCoin) and let users import minting service contract XMLs (into their BitCoin client).
Each XML describes how the minting service works, what the protocol parameters are and basically how the coin creation is initialized. This way, they can all live within the BitCoin network, but it remains to the users to decide which minting services to use.
This allows the entire network to increase the money supply (of course, with different types of currency), gets rid of voting and doesn't "force" users to use a specific currency.