https://bitcointalk.org/index.php?topic=427519.0 - Check out this experiment which is related, known as Premine coin. All of the coins are already in circulation, the coins were given out to anyone over 30 day period. You can see how the network behaves when a coin is nearing the end of its life in regards to the getBlockReward value. It won't be exactly like Bitcoin since it is not as valuable but you can study several of the qualities it has.