Most major banks have med student loan programs (ie, Wells Fargo, Citibank, Bank of America, etc.). The problem is that they need to get approval from your financial aid office first. Your financial aid office will probably approve you for loans to cover the estimated budget for the year (tuition, books, fees, housing costs, etc.). However, if you feel like the budget is unrealistic, and thus you need more money on top of that, most banks will not be able to help you, because your FAO will most likely say no. The one program I have found that does not need approval from your FAO is P.L.U.S. -- keep in mind that their interest rate is fairly high as are the associated fees, and you may also need a co-signer. (All this info. is based on my dealings with UCSD).
I think I recall you posting that you are going to a UC -- Fiatslug (UCI) had some luck with her FAO by saving ALL her receipts and thus managed to get extra loans to reimburse moving expenses, apartment start-up costs (lamps, etc.), drug co-pays, health insurance fees, etc. If you are at UCI, you might want to try emailing her for advice.