I wonder how something like the SIAI SF.260 would work in the role.
It's still in production and available in turboprop as well as piston versions.
It can be fitted with gun and rocket pods. It's aerboatic and would present a quite small target itself.
The second seat could be pulled out and the space used for extra fuel or avionics.
It might not be able to take the more heavily armored, dedicated gunships, but there's a whole lot of lighter helicopters out there that I imagine would be in tough against it.