I agree that leaving a dog alone for 12 hours would suck for the dog, but it's better than death. We got our black lab first and realized very quickly we would need a fence so we had one built. They get walked once or twice a day and are free to go out into the back yard whenever they please. I work a 9 - 5 and she works overnight, they have a bit of alone time as she sleeps during the day while I'm out ad vice versa but they both seem very happy. Having two helps though as they can play with each other most of the day
If you have a fenced in yard you could always get one of these.
http://www.petco.com/N_22_136_30_505...5059&cmrefpf=1