Thanks, everyone, for your response. We actually talked about grade skipping DS and then if it didn't work out putting him back in 1st grade, but they were adamantly opposed. They think it is more harmful for a kid to go to 2nd grade and then drop down to 1st grade if it didn't "work", than a 1st grader being moved up to 2nd. I told them I totally disagreed. They also said that if in the first two weeks of school the teacher noticed that he is ready for 2nd grade then they would move him, but really I think they just say that to try and make me feel better.
I have since given to the principal the IAS and "A Nation Deceived" . Don't know if he read it, but I basically told him it is very interesting and might give him insight into why the other grade skip didn't work.

I will be pushing for differentiation, at the very least, and I think they will wholeheartedly go for that, so it may not be so bad after all. We shall see.