Webjockey, is he in kindergarten right now? Yes, I hear you on the Montessori schools. I posted on here a while back about how we had issues with DS when he was three and attended a Montessori preschool. I feel like some private schools in general don't want to accept "difficult" children.
If your son has ADHD, are you going to try medication? I have such mixed feeling about that. No one has suggested that our DS has ADHD, but I've thought about what we'd do if that were an issue. I don't like the idea of medicating for behavior that I think is normal in kids, but when I was a teacher, I had one student who was so much more focused and behaved when he was taking medication.
I was very very hesitant to get DS evaluated a couple months ago at his public kindergarten. We had an evaluation about 1.5 years ago at a clinic that I trust completely, which found that he has expressive and receptive speech/language delays. I feared the school would come up with a long ridiculous list of what was "wrong" with him. But the only area that was outside the normal range was speech articulation--the expressive and receptive language were now normal. I still feel like he's not quite caught up in those areas, though.