A bunch of British universities have mooted the idea of a graduate tax, where college graduates pay a slightly higher tax (on incomes over a certain threshold) for the rest of their working lives. [The idea is that their college education would either be free or cost very little].
This is a variant of the Australian model in which graduates pay a slightly higher tax (on their income exceeding a certain threshold) only to the extent of what they owe the government for the cost of their college education.
In his recent speech at IISc, HRD Minister Kapil Sibal talked about the creation of an Education Finance Corporation (or some such entity) that will guarantee bank loans for higher education; the idea, then, is that banks would feel far more comfortable lending to college students -- even without a collateral. The educational loan would come at a low interest rate -- Sibal mentioned the possibility of 4%.
I have been a fan of the Australian model, myself. (a) It has the virtue of making college education affordable for everyone -- especially the poor. Decisions about going to college would no longer involve the financial implications of the move (other than, perhaps, the opportunity cost of spending four years pursuing a degree). (b) The burden of repayment is light. (c) Repayments kick in only when incomes exceed a certain amount (which is pegged to the median salary). (d) Unlike an educational loan, this model doesn't penalize those who are forced to drop out of college. And (e) it has lots of flexibility in terms of inflation adjustment, quicker repayment schedule, etc.