Hey Sean,
Welcome to BP! First consider Joint Ventures where the money would be more private than financed. Second, HML or Hard Money Lenders will require alot up front but are heavy in the rehab scene and if they are more asset based will lend on the strengths of the deal. Interest and points are going to be high on those loans. A financial institution may have short term loans but are going to have some pretty strict guidelines and unless you have a good relationship with the loan manager at the financial institution probably is not going to be the best option for you.
Of course if you could leverage a personal or business Line of Credit to supplement your cash that could help you out with out actually having to get a loan from a bank to rehab and wholesale. And LInes of Credit have simple interest so in the end could and should work out pretty well for you. I also know that there are transnational lenders out there that can help you wholesale depending on the laws in the state you are wholesaling in. For wholesaling I would recommend you look into transnational lenders but be wary of how they work and what you are doing so that way you can make the profits you would like by using them.
There are many folks on this site that can be those private investors for you in doing deals just remember to treat their money as sacred and that the returns expected are returned.
Good Hunting and Happy Investing!!