"The placement cost $50K plus and was paid for by the School District of the student’s home. So, regardless of the severity of the disability, the District is responsible." 

What happens for children in rural areas where the school has 100 or fewer students? Is there state funding or must the school district cover it all? I can imaging that a severely disabled child might need a boarding school which could equal the cost of two teachers at a grade school that has a total of 4 teachers.  The other 100 students would be severely impacted by class size of 50 instead of 25.