Loan agreements, like any contract, reflect an "offer," the "acceptance of the offer," "consideration," and can only involve situations that are "legal" (a term loan agreement involving heroin drug sales is not "legal"). Loan agreements are documented via their commitment letters, agreements that reflect the understandings reached between the involved parties, a promissory note, and a collateral agreement (such as a mortgage or a personal guarantee). Loan agreements offered by regulated banks are different from those that are offered by finance companies in that banks receive a "banking charter" granted as a privilege and involving the "public trust."
Private student Loans is another alternative that comes into force rescuing students who have a bad credit history. I have heard of many cases where students apply for loans as a supplement with their Stafford or Perkins loans. In other cases, I have seen people applying for student loans with private organizations when their Stafford loan amount comes to an end.
Be careful applying for private loans with banks. If your bank requires a co-borrower to sign on the agreement before the loan is sanctioned, make sure that your co-borrower has a good enough credit history. Not having a good credit history could jeopardize your chances of getting the private student loan that you would have otherwise got stand alone.
If you have high repaying capacity, then it is advisable that you opt for less number of years for repaying the loan as it will reduce the overall burden of the interest. Though you are ready for repaying the loan as quickly as possible, but if you miss to mention this in the loan agreement, it would be tough to alter once the application is processed by the organization that is lending you the money.