The per-lot taxes you suggest are increasingly the way things are financed in California: it's called a parcel tax and when a city wants to raise money for schools and the like, it's one of their few options for passing a new tax, since they've already maxed out the property tax allowed under Prop 13. The other major option for new taxes is sales taxes, but those create a perverse incentive for cities to maximize the number of car dealerships and other commercial property and minimize the amount of new housing they allow, since it's stores that pay property taxes, while houses tend to consume more city resources while paying fewer taxes.