There is a company working towards this that I believe has been mentioned here on HN before: https://www.legends.solar/get-early-access?grsf=texm9h (Feel free to lop off my referral code).

I'd argue that this is likely more challenging than it seems, with city/state/county building codes, plus just building on existing dense spaces, and add to that any grid/utility policies and associated costs to play ball