Well, I've tried to work with customer services and they won't be cajoled, drawn, pushed or pulled into doing anything about this.
I regard this as a serious failing on their part. Their emails just keep reiterating security precautions which users should take: I've been through all of these and can't see how any passwords leaked from the client side.
I guess we just keep tabs on the situation and see if any more compromises happen - who knows, perhaps Apple have tracked down the issue and fixed it? The volume of compromised accounts with Taiwan downloads seems to be diminishing from the search results I have.
Apple's one-approach-fits-all culture of silence (by which i mean pleasant form-email) doesn't feel like a good fit for this kind of issue. It leaves the situation unresolved, with the user not entirely sure if they're safe or not.
I'm only thankful that this happened to my wife's account, not mine: 2 factor auth should be available to me in a day or so.
If anyone comes across this thread, and has a Taiwan-related unauthorised apple I'd use scenario, please add your story to it. At least if the posts die off we can *assume* the issue is as well.