This is an excellent article on one family's unique approach to education. Their kids are earning bachelor's degrees in their teens and even wrapping up doctorates in their early to mid 20's. How to send a kid to college by age 12 | MNN - Mother Nature Network
Wow! I thought we were ahead by homeschooling and getting our son into college at 16. However, having a child begin college work at 12 is a bit of a stretch IMO. It adds a great deal of stress at an already critical time in their childhood development.
My wife was more intrigued than I expected and we ended up talking to our oldest two kids this evening about what they would see as pros/cons of going at their own pace but starting college studies before their peers.