There's a plan here in Oregon to try and work up a viable system to do this. The idea is called "Pay it Forward" and you would essentially pay a 3% tax for 20 years after you graduate. I'm not entirely sure it will ever come to pass, but it's not a terrible idea IMO. It may not save money, but it does mean you get an automatic income based repayment plan, you can never be in default and you get an automatic deferral when unemployed.
That said, it doesn't really do anything to fix the problem of skyrocketing education costs which is less than idea...
That said, it doesn't really do anything to fix the problem of skyrocketing education costs which is less than idea...