What a tough situation! I'm not sure I'd be pulling my ds after only a week ... but I can't say I *wouldn't* be either. If there's a clear mismatch and you know it right away, no point making the kid suffer.
I wanted to put a word in for Montessori. My ds6 entered Montessori Early Childhood when he was 4y3m (switch from normal "daycare") and absolutely thrived there. He entered reading fairly simple books (Dr. Seuss and the like) and 8 months later he was at a mid-third grade level. He was allowed to do higher place value in math (he was at 10,000s when he left at 5y1m) and start learning multiplication. So he certainly wasn't being held back, and being allowed to push forward at his own pace -- something that wouldn't have happened in a standard setting.
Obviously, this isn't all due to the school -- but it *was* in part due to the opportunity to explore during the day. It was play in his eyes, but directed, goal-setting play.
And my favorite part about it was that there was focus on self-help and independence; my ds is an only child and gets a *lot* of coddling at home.
And there was a strong focus on interpersonal skills -- peer teaching, group problem solving, etc. So not only was he growing academically, but he was growing personally and learning to make connections with other kids.
Obviously, Montessori isn't the only way to go ... but it is a great philosophy to look in to with a young gifted kid. And obviously, what Kriston said. All Montessori schools, like all private schools and all public schools and *all* schools, are only as good as their teachers and administrators. Go on a few observation days.
You may also want to look at gifted schools in your area. We're switching to a private gifted school after a disastrous year in public K. At the new school, the kids are divided into groups of 3 or 4 for core subjects based on ability, but have age-appropriate, two-year homerooms for gym, art, music, and writing (ds will be in a 1st/2nd split room this year). I love that they separate reading and writing, so a kid who writes like a 5yo but reads like a 10yo is able to progress in *both* those skills independently. I know my ds's school has a preK program ... maybe there's something like that near you?
Good luck! I hope your poor ds isn't too traumatized.
