I came across this website about a new independent 529 plan for private colleges. It is sponsored by more than 250+ schools including some of the very best such as Princeton, Stanford and MIT. Since my older son will start college next year, I am thinking of prepaying 4 years of his tuition as soon as he decides on a school. It will save a little bit of tuition and tax on the investment gain.
For people who can't find a better investment return than the tuition inflation (about 6%), this could be a reasonable option. More information can be found at its website, http://www.independent529plan.org.