"Yes, his previously bad preschool behavior was directly correlated to lack of challenge"

How do you know that they were correlated? I'm trying to decide if the angry, rebellious, obnoxious behavior I'm seeing at home (everything is wonderful everywhere else!) is related to boredom/lack of challenge at school. My son is 6 and in 1st grade. He's reading at 4th level and the teacher only lets him read middle 2nd. I don't have any idea what level math he can do but at school he's doing single digit subtraction and addition. Teacher has been unwilling to make ANY changes. My son says that school is "okay". He likes PE, Recess, art, music the best.

My goal: happy, healthy, responsible, ready to think and tackle what life hands him. He has so many interests but with being in school 7 hours a day and already doing piano, karate, and soccer, we have very little time for play and exploring and learning Roman numerals and stuff that interests him. He also wants to add boy scouts and gymnastics.

My ideal school would be one that grouped kids together (regardless of age, like the old one-room schoolhouse) and let them learn at their own rate maybe 4 hours a day. Then, we could play and explore and add activities. I know I'm chiming in late here, and I couldn't figure out how to make the quote thing work, so I just copied and pasted. I'm really interested in what made you so sure the behavior was linked to school.