I've been looking and I can't find anywhere.
Most places have rates way below ours and more mitigation. For example, in Massachusetts most schools that are doing in person learning seem to be doing a hybrid half in school / half at home model with masks all the time, social distancing all the time and small class sizes that the hybrid schooling allows.
Unsurprisingly my friends there have a rate of under 40/100k whereas ours is now well over 500/100k (we're tier 4 of course but our schools apparently still opening with no social distancing and no masks next week - primary). We had about the same rates in the summer. So it seems opening schools without those mitigations isn't the best idea.
In new york they seem to want to close schools when positivity goes over 3%, although are reviewing that - and doing whole school testing using trained teams that go from school to school (yes, no getting the teachers to do it on their breaks!). Note the article mentions they have social distancing in schools and I know they have masks - so they have mitigations UK schools don't have. www.nytimes.com/2020/12/07/nyregion/nyc-school-reopening.html
Is there anywhere else in the world contemplating this madness? No mitigation against airborne spread and opening at rates over 500/100k population?