Sidelines guy here, with a half baked suggestion...

I wonder how practical a "Nielson Method" approach might be?  As in, you set up a bunch of routers with internal data gathering and reporting ,  and give them to a few hundred households... 

I can see that to do that would be a not insignificant undertaking itself, as well as managing it...  and you'd never have as much data on what's happening in the houses when X happens as you might like,   but it would beat renting lots of houses.