Clearly there aren't such worthwhile loads available, which is why the rates go negative in the first place.
>pre-cooling of buildings during the summer (run the AC in houses full blast during the middle of the day so there's no need to run it in the early evening),
Isn't this counter-productive? The middle of the day is also when the temperature is the hottest, so running AC full blast is also the most wasteful since it generates the biggest temperature gradient (and thus cooling loss).