@David Smith, I think 5-units are the toughest properties to invest in. To directly answer your question, I'd look at community banks for financing as they'll be your best (and maybe only) option.
Here's why I'm not a huge fan of a 5-unit: 4-units are treated as personal properties and you can get personal loans on them--30-yr fixed rate. 5-units are commercial properties, so you are you looking at whatever terms you can get from a bank. Best case, that's likely going to be 25-yr amortization with a 5-, 7-, or 10-year term, and an interest rate higher than you'd receive on a duplex or fourplex. Operationally, the 5-unit isn't going to be much more efficient than a 4-unit but the bank terms are far inferior.
I wrote an article a while back about how we built our portfolio--step #4 is buying in your name to take advantage of those loans. I'm not saying you can't make money buying 5-units but I'd really encourage you to either find a 4-unit or look for a 10+ unit.
Best of luck!