There certainly are many private schools in the Bay Area and S.F. area that call themselves schools for gifted students.
Well...I don't know about the "many" part, but there are a few here. Nueva uses IQ tests, but as far as I know, it's the only one. Harker recruits gifted kids, but I'm pretty sure their policies are achievement-based (not dissing Harker; my understanding is that they don't use IQ tests). I've heard good things about Harker's high school from a DYS parent. There's also a school in Santa Cruz, but they did an interview in a local magazine two or three years ago and the teachers they interviewed were saying that everyone evens out by third grade, including those amazing kids who learn to read when they were two (paraphrase: "reading is a milestone like walking; you don't hear about eight-year-old 'gifted walkers'").
Two of my kids go to a small private school in the Valley that's all about individual pacing. I asked them to place my daughter (10) in algebra 1, and they were wonderful about going ahead and doing it. They said they'd try it to see how it worked out, and it's been fine so far.
