Make a client for users and a bitcoind for miners and pools that simply does not processes certain addresses that you are against.  Then publicize and distribute that client.  If you get 51% of the miners to follow you, you win!   It is not a whole lot of code just to ignore the addresses either.   Then when someone tries to move those coins, the network will fork.  If you have enough on your side the network will re-organize every time a block is mined with those coins and revert back to your fork without those coins moving.