Alabama up until recently offered a prepaid tuition program that you could pay into, and then it guaranteed to pay your tuition at any Alabama public university. This was a public trust, and I don't know how similar other states' implementation is, but if there are any companies that offer the financial management of such a program, it would make sense to invest in that.

I suppose if you were really serious about making that bet, you could form a company that offered a similar investment service. Sell the product at a price that assumes the current rate of tuition inflation, and then rake in the cash when it doesn't happen.