A big thanks to everyone who shared with me their advice on how to approach our school meeting to talk about appropriate placement for our son.
The meeting went extremely well, in large part because of how prepared we were. We utilized many of the resources suggested in this thread.
I have to say that we feel extremely fortunate that we have a private, gifted school right here in our backyard. The meeting began with the school selling us on why our child will flourish at their school. They said all the right things about the differences between gifted and highly gifted, etc. We walked away feeling as if they totally get it, mostly because they discussed the multitude of ways that they will ensure that even a highly gifted child's individual needs will be met. And yeah, there was no discussion of problems with sports, handwriting, or dating.

There was much healthy discussion about starting our son in 2nd grade, instead of 1st - and they suggested, based on his scores and academic age, to evaluate and assess him with a 2nd grade teacher. If he truly is ready in the majority of areas for 2nd grade then they will place him there and work with him to make sure he is getting what he needs. If he appears to only be very ahead in one or two areas they will make those accommodations from his 1st grade classroom.
They even brought up the reverse issues, suggesting that he needn't be pulled out of Tai Kwon Do (which is part of the academic curriculum) because it is more cerebral than athletic but suggested we should consider having him to take PE with younger kids.

We feel like we couldn't have stumbled on a better scenario for our child. He is going to get to begin his formal education with the most appropriate placement and IEP right from the beginning.
And most importantly he so excited to begin "real" school.

I will keep you posted on how the assessment goes on Tuesday and if it will be 1st or 2nd this year.

Thanks to all of your comments we went in feeling that either placement could work well. Now we are leaving it in the teacher's hands. Ultimately, she has to support the radical three year grade skip or it won't be successful.

I'll be writing in for lots more input as the months pass.

Thanks again!