Currently you can get the grim reaper achievement by queuing with the new world queue thingy. If you switch from one battleground to the next you keep your honorable kills from the last one and can get the achievement.
I'm not sure if this would work for the 300,000 damage achievement, but if it would that would be sweet (for lower levels to get).
I don't have a SS, but if someone puts one up i'll rep you for helping the thread.