Bandwidth monitoring by device

I've been searching the forums and the Internet in general, today, as I have gotten my first notice from Comcast that, lo, I am over my 1 Terabyte limit, this month. It has been inching toward that mark for a bit, and last month was around 944 Gig. What can I say: We are a connected, gaming, streaming family and our Comcast link is a vital utility. I have seen suggestions on this forum to "just disconnect everything and reconnect until you find the hog." With 30ish devices on the network, 4 kids, 2 renters, and countless visitors, this is simply not a possibility. What I could do is set up a different router (preferably one with this feature) and move the connections over to it one-by-one until I find the offender. If I have to go that route, I highly doubt the Orbi would get reconnected. Which is a shame because it is a pretty decent solution for everything else.

I would like for Netgear to seriously consider giving customers an option for this data. There are many ways to do it, but ANY of them would be acceptable to me. I'm a long-time networking pro, so even if these are scary for some people, at least it would be an option. 

1. Do the metering in the device with display of the statistics in the interface and in the app. This is obviously going to make the most customers happy because it would give us a report per-device of the usage. This isn't rocket science: Even if the device has a database limitation of 100 devices to monitor, or even 50, it would be useful. COMCAST does it on their modem devices for xFi. It can't be that hard.
2. Do the metering externally by providing SNMP statistics on a per-device basis for smaller timeframes. This would mean that the Orbi doesn't have to store "dead" devices forever and would be up to whatever stat-gathering tool was used.
3. Do the metering externally by providing some app that collects the data to a desktop. Maybe Java so you can hit Windows, Linux, and Mac all at once with it.
4. Provide traffic mirroring to a selected wired port. This would at least give me the ability to plug in Wireshark or other tools to see what is going on. It would be super useful for troubleshooting intermittent issues and not just bandwidth monitoring.
5. Provide netflow/sflow output to a collector on the home network. This would also have broader uses than just bandwidth monitoring, but it is potentially the hardest to use solution in this list. If it is easy to implement in the Orbi (i.e., the chips already support it), then I'll take it happily.
6. Other things I haven't mentioned. Look, I'm desperate, here. I will find a way to use anything that helps.

I get 2 months free "warnings" from Comcast, but the cost of not knowing this outweighs replacing the Orbi. Once I start getting charged $10/50 Gig, I'm going to need to know right then and there. And if I don't have a reasonable answer by that time, another Orbi will be going out to eBay.