The Legislative Budget and Finance Committee (LBFC) issued their report on the fiscal benefits of consolidating school districts. Their findings were that districts with 2,500 to 3,000 spend somewhat less per pupil than those with few, and those with more students. This is consistent with my own analysis of data (see below).
The report suggests that consolidating some smaller districts (only if other small districts are adjacent) could lead to minor savings. They do not suggest breaking up larger districts, however, which would also be a natural conclusion.