HELOC on free and clear rental in Denver

Can anyone recommend a financial institution (bank, credit union, etc) in the Denver area that will do a HELOC on a rental property that's owned free and clear? I want the money to pay cash for flips. I'm using this strategy with a HELOC on my primary residence already and it has worked out well for me. I like the flexibility of a HELOC verses a cash out refiance because I can use the money over and over again by paying off the HELOC between flips and pulling it back out when I get the next property without having to pay the interest I would have to if it were a cash out refinance when the money wasn't being used between flips. (unless someone can convince me otherwise)

Thanks