Replace chairs with bicycle generators. Kids have to peda if they want light and heat.
All older children take younger siblings to school and take turns providing daycare for them.
Add a baking class, sell school-made challah to parents.
Kollel students teach all religious classes.
Children make their own paper
Classes taught in large lecture halls (though the size of classes now, it seems to be heading that way)
All kids at a certain age (maybe 15) spend 1 year away from their studies and teach younger kids