We have a huge inventory of duplexes up here in Milwaukee across all price ranges and we have closed quite a few of them with clients this year, but you'll have to trade AC in the summer for heat in the winter ;-)
There are lots of great markets throughout the country. I'd first define a state you want to live in then define a specific market. The great thing about a house hack is the risk is relatively low since you will be very hands on (living on the property).