Nice writeup! I think it’s worth noting that batchTransfer isn’t a standard ERC20 function so only the contract owners which chose to implement it could be effected. Couple of questions:

1. Since batchTransfer isn’t a standard implementation, did the other contracts you found share the same implementation or were they slightly different but vulnerable to the same exploit?
2. If they were the same do you have any idea of the origin of the function? I tried to find any reference to a batchTransfer implementation in zeppelin-solidity but there is none, as an example.

I’ve got a feeling that this could be something like an outsourced company who’s creating tokens for new companies with a vulnerable template.