That's exactly what I have done (for the prototype) and will do (for the actual client). However adding demurrage is a protocol-level change and would represent a hard-fork.
It's better for everyone involved to simply start a fresh block chain.
EDIT: But yes, the client would be an open source fork of bitcoin.
Interesting. I guess I was mostly just focused on the bittorrent integration and block-chain pruning elements, both of which sound great for bitcoin.
Just did a very quick skimming trying to understand demurrage currency. Sounds very, very different from normal currency.
From a practical standpoint, would a two-step process make more sense:
1) Widespread adoption of peer-to-peer commodity currency (bitcoin).
2) The implementation of a second peer-to-peer currency on a different basis (demurrage).
Both of these seem like very difficult undertakings. And doing both at the same time seems like it would compound the difficulty.
Apart from Woergi, has there ever been a real-life implementation of a demurrage currency?
Excepting of course the natural cost of storing gold (vaults, guards, etc.). Which is easy for people to accept on a wide scale because its necessity is self-evident.
It's better for everyone involved to simply start a fresh block chain.
EDIT: But yes, the client would be an open source fork of bitcoin.