>> it's not at the point where it would be realistic to have them say "here is a list of a few hundred usernames from SilkRoad spread out all over North America. Find them and murder them all."
This is not exact, unfortunately, because it depends also on some other factors. If the drug lords decide that they want to impose the fact that they don't accept opposition, they are actually going to do exactly that. They've done it already for several bloggers, it would make little difference if they decided to do it for the little indipendent dealers.
Keep in mind that in order to take out a few hundred independent dealears, they only need to torture and kill a few, and have the word spread.