I know a guy whose dad owns a big shop/warehouse -- I think he sells roofing materials, maybe -- and he's adopted, over the years, a number of stray dogs that were loose in the neighborhood, and kept them as 'guard dogs.' They live in the shop, they get fed, they have company when the shop is open but are confined to a yard so they don't bother the customers, and at night they are outdoors with access to a shed where they have beds. They deter people who might intend to come onto the property after hours: they're big dogs -- lots of Rott mixes found in that area -- and they aren't too fond of people when the shop owner isn't there.
That seems like a decent arrangement to me. The dogs get off the street, they are cared for to a decent standard -- the owner's son, my friend, makes sure of that, he's a dog person -- and they are pretty protective of their property. As Jill said, these are dogs that otherwise would have wound up in the pound, or worse.
I know another guy, a firefighter, who adopts strays in the neighborhood of his firehouse and either makes them firehouse dogs, or keeps them. Right now he has a 2-year old Golden/BC girl who is absolutely fabulous and who I WOULD SO LOVE TO HAVE IN MY GROUP! But he loves her too, she's not going anywhere.